Please see the caveats from the Bear and Tree primers.
Please add to those caveats that at the time I began writing this, I'd only actually had a strict feral DPS spec for essentially one and a half raids, so while I think I know what I'm talking about, I may be off a little bit.
Feral DPS is one of the more difficult rotations to pull off. To be great it requires keeping track of 3 boss debuffs, 3 player buffs, and timing cooldowns of these with how much energy and combo points you have and can generate. Our debuffs are two bleed effects and a bleed-damage-increasing effect. Our non-static buffs increase our physical damage by 30% (finishing move, duration varies), increases damage done by 40 for 6 secs (and returns energy!), and reduces the energy cost of all abilities by 50% for 15 secs.
Due to the nature of the beast, Kitties do best on stationary fights where they can simply lock in to their priority system of a rotation and ignore everything else. In ICC, fights like Deathbringer Saurfang and Festergut are pretty much the Cat's meow (I'm sorry, sometimes I can't help being punny.) There is basically no movement and no target switching involved. We get a lot of our DPS from our two bleed effects - Rake and Rip - and the interactions between those, Mangle, and Shred. Yet still, the biggest chunk of our DPS comes from pure melee white damage.
Since one of our most important DPS abilities (Rip) really wants to have 5 combo points every time we use it, and our only AOE ability (Swipe) is too energy-intensive to use for more than a brief burst, we don't tend to shine in fights where there are lots of adds we have to deal with, or lots of target switching for one reason or another.
Even more important than that, though, is Savage Roar. Since it increases the damage done by every attack we do, it is of utmost importance that we keep it up at all times. As you'll see below, it's the highest priority in our stack.
A side effect of this is that one of the most effective gemming strategies for us CAN be to stack Armor Penetration. I will explain that emphasis later.
Also, because you are a Feral Druid, much like bears you will talent yourself into Leader of the Pack, increasing physical critical chance across the raid. Depending on your exact spec, you may or may not provide the random chance of heals that the typical bear talent spec does.
What Everybody Else Needs to Know
What your raid needs to know first and foremost is that if it is possible to assign you a task that lets you rip into a single target (i.e. leave you on Deathwhisper's shield) it will maximize your ability to help the raid. Not that you're useless otherwise, it's just that those types of tasks are how you can put out the most damage you're going to do, and as a DPS that's almost the most important thing you can do.
Secondly, if your raid is cohesive enough to allow for it, Blood DKs should be targeting you with Hysteria in stationary fights as previously mentioned - you can stack all of your buffs with it and it helps every single one of your attacks rather than just some.
Other than that, it's standard Druid stuff - you have a raid-wide static buff (Leader of the Pack, in this case) and a raid-wide castable buff (Mark/Gift of the Wild), and you can Hibernate, Cyclone, Root, and Battle Rez.
This post seems rather underwhelming after my previous entries - perhaps because there's a little less interaction between other players and DPS than there is in the other direction.
Cats don't exactly have a set rotation. They have a priority system, one which can be brutal if you miss on a part of it, but it goes like this, quoted from Elitist Jerks:
1. Keep up Savage Roar
2. Keep up Mangle
3. Keep up Rake
4. Use shred for CP regeneration (remember, that points 2 and 3 are more important)
5. When at 5 CP and Rip is not up, use Rip
6. When below 30 Energy, use TF
7. Use Clearcast Proccs for Shred
8. When at 5 CP and Rip and SR are running with 8 seconds (might be longer, depending on your gear) or longer each, use FB
9. When Rip and SR will drop at nearly the same time (with less than 3 seconds difference), try to recognize it early. Then use SR with a small amount of CP to desynchronize both timers.
10. Use Berserk only at high energy, (but not higher than 85) not directly after TF and as often as possible. If you will get Hysteria or some boss mechanics will enhance your damage, save it for these situations.
With the recent changes to Mangle, keeping it up is easy - hit it once a minute. That's about the only part of this that's really easy.
The post I pulled that from explains a little farther on why some items are further up or down the list. Basically, the idea is that the abilities that buff more things are more important - Savage Roar buffs everything, Mangle buffs Rake, Rip, and Shred, and Rake and Rip buff Shred (but... Rip is less efficient if it's not at 5 CPs).
Among the things I have learned is that one of the quickest ways to get better at Kitty DPS is to understand that while you have to follow this system, you also have to understand the concept of energy efficiency. In other words, if you already have a Rake up, don't Rake again until it falls off. And if it will fall off before your GCD, WAIT for it to fall off, then hit Rake. If you clip the last tick, you have made the energy you spent on your last Rake less efficient. The same is true for Rip, and Savage Roar, although in a slightly different manner.
Being able to wait for the split second it sometimes takes for things to fall off helps in more ways than is immediately apparent. In addition to making the energy you spent more efficient, it forces you to give your energy a small amount of time to regenerate, which means that when you do fire off that next ability, you have more energy to go after the next one immediately, if that is so needed (and it often is).
I have often heard that certain DPS classes have a very smooth rotation. For example, I have some limited exprience with Ret Pallies, and what I have been told bears out my experience - that is, once you start into your rotation, it's fairly smooth - you use whatever ability is off cooldown. Cat abilities (for the most part) don't have cooldowns, so one of the daunting tasks facing a new Cat is understanding which ability it is most important to use when, and why. Hopefully, between the explanations above and those coming when I go through Specs and Glyphs will make the whys a little more clear.
Whew. That was a long time coming! I (can't) promise the next post will come quicker (but I expect it will)!