Maybe Matty is sleeping at a friend's one night, and Jack goes out and gets picked up by a cute guy with light brown hair and hazel eyes who smiles so sweetly up at him.. he doesn't understand what it is that attracts him so much to the kid until they're hooking up and the young man calls him daddy. (You can age Matty up if you like, or Jack can wallow in shame and self-disgust and the ohgodwhy feels afterwards- either way, I'm into it!)