This is my FAQ which I also posted in the VN Necromancer forum, here, but this version is more up-to-date. If you have anything to contribute to this FAQ, please contact me there, Silicon Dragon

I've gathered as much information possible regarding the Necro Facilitate Painworking (FP) spell. I'm posting it here for everyone for everyone to share. I'm sure there are missing tidbits here and there, but this will hopefully become part of a larger living topic thread some day.

FP is different than Quickcast for other casters. You cast FP and then have 6 secs for your servant (i.e. pet) to cast spells uninterrupted. Here are some tips on using FP, using the powertap spell (PT) as the offensive spell used in this FAQ.

Q: What are the steps for getting FP to work correctly?
A: Wait for the pet to finish his current melee action, make sure your spell queue is empty, cast FP, and then immediately cast PT. Most players claim that your pet needs to be in Defensive mode, but several players (including myself) have gotten FP to work reliably in Passive mode. (See "Does FP work when the pet is set on Passive?")

Q: Does FP work reliably?
A: Yes, but make sure that your spell queue is empty PRIOR to casting FP. It also helps to cast both FP and PT just before the pet begins his next melee attack. It's easier to learn how to use FP while your pet is in Defensive mode, but with additional practice, you can use it just as reliably in Passive mode as well.
Note: To increase reliability, see "Is timing important?" below.

Q: Can you cast 2 PT's using FP?
A: Yes, if you time it right and practice this technique, you can do it reliably evey time. Once the pet begins casting the 1st PT, immediately cast your 2nd PT. See "Is timing important?" and "Can I spam a spellcast button?" to help with timing issues.

Q: Is timing important?
A: Yes! You can cast FP any time after the pet completes its current melee action. However, with practice, you can reliably cast 2 PT spells. The trick is casting FP + PT just PRIOR to the pet beginning its next melee swing, thus getting the least delay between when you cast FP and when you can cast your 2nd PT; this is extremely important because you need to cast the 2nd PT before FP's 6-second timer expires.
Addendum: For pre-bommie pets (i.e. 1H pets), you can increase your reliability even more by inserting a .5 - 1 sec delay between when you cast FP and PT. Thus, for best results, use the following sequence: FP, 1s delay, PT, wait for PT to begin casting, then continue casting spells normally.

Q: When is it safe to cast a 2nd PT?
A: Cast the 2nd PT once you see the pet begin casting the 1st PT (some people wait for the audio, others watch the pet).
Warning: If you cast your 2nd PT before the pet begins casting the 1st PT, the 2nd PT will ruin the FP and both PT spells (see "Can I spam a spellcast button?").

Q: After hitting FP, do you wait for the icon to show up in the pet window before casting PT?
A: No, cast PT immediately after casting FP. There is both lag and various coding bugs associated with the pet window updating properly; occasionally, FP won't show up in the pet window at all! If you wait for the icon to show up in the pet window, you'll likely have lost all the time required for casting your PT; end result = no spells cast except FP itself AND you lose the power for each PT cast.

Q: Can I spam a spellcast button?
A: Definitely not! A bug in Mythic's Necro spell queue prevents this from working. If you ever have 2 spells in your queue and you begin casting a 3rd spell, it'll cancel the 1st spell you've already got in the queue, move your 2nd queued spell to the head of the queue, and insert your new spell into the queue. In the case of FP + PT in your queue, if you hit a 2nd PT before FP has been cast, your FP will be cancelled and you'll have 2 PTs in your queue, both of which will then fail; 3 spells will be wasted along with their time and power consumption. Thus, do NOT spam your spellcast buttons!

Q: Does FP work when the pet is set on Passive mode?
A: Yes, but it's much easier learning how to use FP while the pet is in Defensive mode as timing is more of an issue. However, because many foes in RvR rely heavily on reactionary styles (especially stealthers!), you might want to practice using FP in Passive mode, especially if you don't like having your pet melee-slowed or -stunned.

Q: Does the caster and pet have separate spell queues?
A: Yes. It is possible to queue 2 spells with the necro pet and then immediately queue 2 spells which are cast by the shade. This means that with 4 quick keystrokes you can effectively queue up ot 4 spells at once.

Q: What happens if you cast FP, the pet swings, and THEN you cast PT?
A: If the pet casts FP and starts a melee attack before PT is inserted into the spell queue, the PT will stay queued until the pet completes his melee attack, and that's wasted FP time (remember, FP has a 6-sec duration). This is especially bad when you get to level 45 and can summon an Abommination which has a 5-second swing delay.

I hope this Q&A helps everyone learn to use FP better and more reliably. The 1 piece of info that new Necro players will remember is this: timing. Master timing of FP and queueing your spells, and you'll find FP to be better than the common Quickcast spell of other caster classes.

Ammendment on using FP in Passive mode.

I been requested to better explain how I use FP while the pet is in Passive mode, so here goes...

In Defense mode, what works best for me is casting FP just before the pet swings*; whereas in Passive mode, I cast FP just after the mob swings. This works for me, but then I may be doing things slightly different than normal people**.

Why?

I reasoned that if the mob is interrupting normal casts, maybe it affects FP in the same way, possibly only when I haven't cast the spell following FP before the mob begins his next attack. If such is the case, I reasoned that I'd need as much time as possible to cast both FP and the 1st offensive spell. Once the pet begins casting the offensive spell, the "non-interrupt" mechanism would easily allow a 2nd offensive spell to be cast. To make a long story short, it seemed to work fine for me. Therefore, I'm guessing that the mob can interrupt FP, just not the spells cast in the 6 secs following FP. I can't positively say that this is The method, but it works for me, and no more/less often Passive mode than in Defense mode.

Note:

It's just my hunch, but FP's success might also have something to do with how the pet reacts to a mob's melee hits. On Passive, the pet never swings his weapon, but it often {but not always} seems to flail his arms around every few secs, just as if he was meleeing. (What a weird bug!).

* Like AzazaZazaza said, FP actually casts when the pet would normally be performing a melee swing.

** Based on the many comments on other people using FP, it seems that most people find FP relatively easy to learn. For some reason, I found FP very hard to learn. When I stopped paying attention to the graphics and audio for timing my FP casting, everything seemed to fall into place, and FP has worked fairly reliably ever since. And if it helps anyone, I actually begin counting "one one thousand, two one thousand, ..." in my head. For instance, when I go to cast my 2nd offensive spell following FP, it's "one one thousand, two one thousand, three one--CAST!" Yes, it's dopey, but it works well for me.

Here's another comment by DrRothchild (used w/ permission) that may better help explain how to use FP while in Passive mode:

"I use my FP almost exclusively in passive mode. I've mastered it. I think there is a difference though for it's use in RvR and PvE. In PvE, I pull with the powertaps like everyone and get in 3 or so then as the 3rd one is being casted, I queue up FP like any other spell. Then as soon as I hear the boom, I hit 2 powertaps and wait for one to be cast then hit an exacerbate pain. So after I FP, I get off 2 powertaps plus 1 exac pain this is with 9 in servant. You need at least one dex buff to get off extra spells or forget it. I think the problem is, alot of the time, necros wait until they are in melee to use the FP. Don't wait. Use it right up front to kill the mob fast. My pet hardly every melees or at most takes 1-2 swings. In RvR, my tactic is usually, if we are being swarmed upon, or I glimpse a group, I will hit FP right off the bat because I know a mez is coming and my pet will be useless soon. I can usually get off 1 or 2 lifetaps(I use lifetaps in close quarter RvR because melees and nukers will slaughter the pet). Just my .02."

[updates from robfromaaa, edited]

I also wanted to mention another thing regarding FP. A good portion of the time the reason it doesn't work is because you have a defensive spell queued (like health regen). It is harder to tell when these spells are going to land because you basically cast and forget, but make sure to wait for them, they cause problems a good portion of the time.

I also wanted to make a correction here regarding the spell queues...

The necromancer actually does have 2 separate spell queues, one for the pet and one for the shade.

Give it a try yourself, you should effectively be able to queue up to 4 spells at a time.

2 of the spells have to be of the type that the pet physically casts, and 2 of the spells have to be of the type that the shade physcially casts.

As an example, I can sucessfully queue 2 PBAOE casts, my dmg shield and health regen all with 4 quick keystrokes.

Even better, I can also cast the PBAOE and single target melee DD in the same round, impressive.

Necros do have 2 separate spell queues.

[addition from Waaaaaaaaaaaaaah on dual spell queues and timing in Passive mode]

Aye, the necro and pet definitely have two seperate queues. Simplest way to test this is to hit your Dex, DexQui, and Str (Think thats the order you need to demonstrate queues). You and the pet will be casting the Dex buffs, then the 3rd spell, the str buff will be cast.

Also, I don't think there's any need to time the FP and PT so you're queueing the spells right before the pet swings. With the abomination and his polearm-speed swing time, I hit FP, PT right Both spells are cast when the pet would make his next melee attack, meaning FP starts when he would swing again, not when you hit the quickkey for the spell. He'll always get two PTs off with this method.

[self-comment on Passive, Defensive, and Aggressive]

Aye, I use qbar macros for pet window commands, though I use Passive mostly while travelling or fighting near structures (incl. dungeons). Even while PLing others, I keep the pet on Passive so I can fire-off an AE Str/Con debuff a tad quicker for peeling mobs that attack the PLees; but I slap the Attack button quickly which, of course, moves the pet to Defensive mode as well.

Btw, in case anybody was wondering, Aggressive works identically to Defensive mode as far as FP is concerned. I've been using it more frequently of late because it's better at uncovering enemy stealthers.

[reply from Nostruum & myself, a good note on dual spell queues, using HoT and insta LTs]

Nostruum:
"I have learned that I can cast FP setup a PT, when the first PT starts casting hit a second PT and start casting 2 instant LT. If you time this right the first LT will go off immediately after the second PT and before the pet swings and you will be casting the second LT thus insuring that you have two queued after the next swing if you queue a third instant LT as soon as the PT and first LT go off. Sometimes I substitute a HoT for one of the instant LT if I think I'm going to get alot of resists."

Self:
"Yup, that's the sequence I usually use. If you've got good healer buffs, you can usually get in 3 PTs, though, and it's sometimes worth the risk rather than starting the 2 LTs right away.

Against red/grape mobs, I usually sub my 2nd PT with a HoT, but usually not unless I can start with a HoT prior to my first pull which begins melee with 8-10 seconds of HoT remaining."

[self-comment on pet stuns and spell queues]

Btw, if your pet is stunned and you have spells in the queues, spells will be suspended, not lost; this means that when your pet's stun wears-out, it'll resume casting spells that were queued-up at the time it was stunned. Thus, here are some tips on using FP when faced with potential pet-stunned situations:

1. If you cast FP and any subsequent spells and THEN the pet gets stunned, FP and the 1st spell will be cast while the pet is stunned, but you can't queue-up any other spells until the stun wears off.

2. If you cast FP and then the pet gets stunned, the FP reset-timer continues to tick away. Thus, if the stun last longer than 30 seconds, you'll be able to use FP right away.

3. Be careful using FP when the pet gets stunned. If FP is cast by the pet prior to being stunned, the 6-secs of FP-immunity will likely expire before the stun wears off, meaning that any new queued spells won't be covered by FP's 6-sec effect.

[self-tip to reduce chance of pet being stunned, especially by stealthers]

If your pet is on Defensive or Aggressive and it attacks a foe which potentially has reactive styles (all RvR foes and some PvE mobs), the foe can use an "after block/parry/evade/etc" style with a stun effect, thus stunning your pet for up to 9 seconds. Thus, special caution needs to be used when fighting foes that frequently use stun-styles, especially stealthers who can easily kill your pet before the stun wears off.

For example, when fighting a stealther, get the pet on Passive ASAP. If the pet swings even once against a stealther, your blow is almost guaranteed to be evaded* and setting up yourself for a counter stun-style attack. Heck, assassins even have enough time to restealth and PA your pet before the initial stun wears off; if that doesn't kill the pet outright, the following PA-chain styles surely will.

* Remember: the pet cons blue to the stealther, so it's VERY easy for a stealther to evade your pet's attacks.