Sexual act.
A woman allows her partner or partners to nurse off her while having sex. This is very easy due to the engorgement of blood to the breasts.
Girl: I'm a milk momma! Want to come over and have a drink?
Guy: Can I bring a friend or two?
The Milk Fic is a short two part story about Ryan Ross and Brendon Urie. It consists of Ryan drinking a ton of milk and then "releasing" it, to make his rear taste better. Then they f*ck.
Ryan was kneeling in the bathtub, a towel under his knees.
Sike! No way am I typing that, get some bleach and holy water
Friend: Hey, what's the milk fic?
Me: *spits out tea* get the holy water...
Me: The milk fic is a fan fiction about Brendon Urie and Ryan Ross being in a sexual relationship, many fan's hate it, due to the amount of kinks. You have to admit the author was creative.
This MAY be a flash video like tommy says, but this is actually a popular song from G love and Special Sauce. It was a song BEFORE it was a video of two guy singing it(obviously).