Looking for a specific story about witches

[peachknight]

I remember reading this story about a guy who is used for a couple witches spell. They put him under a mind control spell and basically milk him. Each time he cums, the use his semen to make their breasts grow bigger. To get bigger breasts, they take away a few months of his life force. He finds out by pure luck when he has computer audio recording one of the encounters and he plays it back. He somehow reverses the tables by finding a loophole in the spell that trades him the girls as sex slaves in the price of the girls wanting bigger breasts.

They are all in highschool. The girls are cheerleaders and the guy is a neighbor to the leader.

If anyone could find the story, that would be amazing.