I'm trying to remember a story I read a few years back but never went back to finish. It started with the male main character going over how to be able to perform magic, you have to pretty much sell your soul to something. The MC wants to do magic, but is unable. It turns out he is a really rare source of magic which has a title I can't remember or I'd probably be able to find the story. Because he is a source, he is immune to all other magic. He gives power to other women by having sex with them. The setting is high school age. I can't remember if I read it here or over on Literotica before I found this site. I hope that's enough for someone to find it. Thanks in advance!