Baby, I'll Bleed You Dry (слэш)

Based on an A/B/O prompt on Tumblr, but with my own twist.
Sherlock is an omega who's been posing as an alpha all along, thanks to these special pills, but when he loses them he is faced with a serious heat. Unequipped to handle it, he enlists the help of Watson, who is eager to help, because after all, what are friends for? ;)
This is a one shot.
Title taken from "Closer" by Kings of Leon