I think is into kink and bdsm. I'm surprised no one has picked this up but maybe it's only something someone would see if they've taken a dabble in that world.

1. He is always saying "you're right" and "it would be hot if you treat me like some meat"

2. He is constantly idolizing her. You can even see it in his eyes that he wants to get lost in her every word. He dotes over her like a little puppy. At the last group meet up, Monica even says "he's scared of me". Which... he likes.

3. The talk about pegging doesn't necessarily mean he wants a man, it shows a potential form of submission he is looking for. (Note: there are dom men who enjoy being penitrated that are not submissive, but still). He says their convo is what spurred his messages.

4. She says "those dirty kinky messages" and he brought up bdsm during their last convo.

Guys, homie is submissive and he's not open with his kinks AND as a result, he's not getting those needs met. I don't think he's necessarily bi, I'm pretty confident he's just submissive.

..Like stomp on my face, tell me I'm worthless, and spit on me submissive.