Looking for mother/son story I read awhile back

[swordancer]

Son is in college and him and his frat(?) have a sort of competition to bang the ugliest(?) older woman. The son gets an older bigger woman and his friend gets his mom without knowing its the son's mom. But he doesn't get that you were supposed to get an ugly woman not just an older. Anyways the son goes into the friends room and has his mom give him a BJ and takes a picture with his phone. As he didn't realize it was his mom till he looks at the picture on the phone cause it was dark in the room.

I can't find this story for the life of me, thanks for the help. =)