Shown off after a hookup

So I'm a first year student in college and I hooked up with a guy last night. He's a senior and he lives off campus and we went to his place and I stayed over there. In the morning, we went at it again and he pulled my wrists over my head, which is hot, and tied my wrists together on his headboard, which was totally hot. We were having great sex for a while and he finished (pulled out and came on me). And kind of relaxed for a bit when he got up to pee and left the door open. And I was like um hello? Are you going to untie me? And he just smiled, and went to the bathroom.

I could hear his roommates walking around but I didn't want to make any noise, and I was kind of panicking. The sheet was covering me from about my belly down but my boobs were totally out and i was obviously naked. And had cum on my belly.

My hookup came in and sat on the bed and was rubbing my boobs and I was whispering for him to close the door and untie me and he was just smiling at me like "It feels like you don't really want me to." His roommate walked by the hallway and looked in and was like "Oh, hello!" and I said "Hi? Could you get your roommate to cover me up?" And my hookup just laughed and his roommate was staring at my boobs and watching my hookup pinch my nipples.

And I said "OK guys, this was fun and all but how about you untie me?" And they laughed. And roommate was like dude is that your cum? And he said sure is! And roommate said gross, man, and left.

And then he untied me.