I have seen people talk about this but I haven't seen people explain it the way my guild does it. I will have screenshots later, realm is down and need to do naxx this week.
1.) You need a hunter to stand in the middle of the room with his pet dismissed.
2.) Everyone else must be on the green hill leading down to the boss.
3.) The hunter misdirects onto the MT and shoots one of the adds.
4.) Hunter feigns death, adds + boss run to the party.
5.) As soon as grand widow reaches the party however she runs back but the adds stay. Down the adds and the boss resets.
6.) You can now down the boss in about 1-2 min depending on DPS.
have fun :P