Greasy Whale Milk

Greasy Whale Milk is dropped by humanoid mobs in Cataclysm zones and instances, predominately from Neferset in Uldum, and Naga and Gilblin in Vashj'ir.

Also, this is sold by Caretaker Movra, Roxa, and Salena Madeux in the Shimmering Expanse, and Quartermaster Rallings and Zan'zata in the Abyssal Depths.

Achievements
Greasy Whale Milk is one of the criteria for Drown Your Sorrows.