True Story, so it won't be quite as spicy. Also some bisexuality included.

So, my wife and I were in an open relationship. I fooled around and she found a steady boyfriend. The boyfriend was a hard luck case and had to move in with us and because I apparently give off massive "dad vibes" he regressed emotionally to a teen.
I'm not naturally a bully, but I also never signed up to raise a 16 year old living in a 30 year old body. So when my wife told me that he was interested in me, submissively; I couldn't help myself.

First, I'd have him suck me when I was bored. If this was fiction, he would say something about "daddy" (father left, big issues) but he didn't need to. He wanted to please. He would get pissy if I said no. I upped it further of course. It got to the point that if he wanted alone time with her (which was at a decreasing rate due to his increasingly submissive nature) I would barge in and take her first, which turned both of them on. He only got sloppy seconds. As time progressed, his couchsurfing (part time worker) was starting to get old. We encouraged him to date and he found someone.

He felt he was safe because I was enthralled by a new game having an open beta, but when I heard that he was going out with the new lady and my wife. I invited myself along, and of course flirted with her and was charming. The next night they went out together and I assumed he got with her. So when she came to visit the next night, I totally put the charm on and we got it on in the main bed.

My wife came in after a little while and told me that L(roommate) was upset because he hadn't been with her. I was surprised, so I unintentionally cucked our roommate and she lost interest in him. We talked a few times, but she wanted a man of her own or at least mostly her own so he never got it.

He didn't hold it against me, he still begged to give me head after that and even after he moved out.