His brother's girlfriends

Unlike John, his brother, Mark, had always been a womanizer, bringing a different girlfriend home everytime he came back from college. All his gfs had always been hotties, that John had admired from a safe distance, trying hard to look through the door lock to see them fucking.

But now he had his powers, nothing was stopping from turning the girlfriends into his slaves and his brother into the biggest cuckold the earth had ever seen.