The first one, the one I completed tonight, is called Unholy Infusion. As you all saw, it doesnt require much from the raid as a whole, except the loss of one dps for P1 and P2.
The next one, Blood Infusion is way harder, and requires special notice from the entire raid. Pasting below some wowhead comments on this...
1) Run in with your tank and get the blood mirror debuff. Have the tank use his shield wall ability while you get guardian spirit/pain suppression/etc. Use your own cooldowns on yourself too - I used icebound fortitude and had my bone shield up, so I didn't drop very low. You only need blood mirror for a second or two. Then back out and let the OT take blood mirror.
2) You now have gushing wound, a debuff that ticks for roughly 1500 damage every second. Make sure your healers know this.
3) If you aren't bitten first, make sure whoever is bites you first. Then you bite three more people during the fight. As you bite your first and second person, gushing wound increases to 3000 damage per second and then 4500 damage per second. When you bite the third person, the debuff is removed, but you are still on the quest and all is still good - you just have no indication of this.
4) Stay alive, kill Blood Queen, turn in quest.
Please post any questions/discussion points in this thread.To be more specific, once you got blood mirror (doesn't matter for how long, you can just run in and have it for a second and that's enough, just don't die) you will get a debuff called gushing wound. Whenever you bite someone as a vampire, you will get an additional stack of this debuff, when you reach 3 stacks (so after you have bitten twice), the next bite will give you the infusion (unlike the other infusion quests, there is no actual Buff for this).
So, during the encounter some guy will get the first bite and after a minute he can bite somebody else (and they both have it) so it goes from 1 guy to 2 people -> 4 -> 8 -> 16 and then you need to kill her or you're going to wipe since you have only 25 people who can get it and you would also hit the enrage otherwise.
Recap: To get this quest done you must be hit by blood mirror (stand on the tank until you have it) and be the first person who gets bitten by whoever gets the first bite from the queen. You must then bite 3 times and afterwards kill her.
A couple small things: You only need the gushing wound before you bite someone for the first time, so you don't have to get it right away. if you die before you've been bitten, you can recover by getting resurrected in time. If you die at any other point, you failed the quest.