Most Helpful Guy
I'm just going to venture a guess that you knew exactly what was about to happen and it excited you. If not you would have told your sister to meet her boyfriend upstairs. Instead you went upstairs and got caught. Now you're trying to convince yourself you did nothing wrong
Most Helpful Girl
Sounds like straight out of the movies. But if this isn't made up, I think he is trying you. Maybe because your sister is not satisfying him? cuz a lover can identify their significant other's eyes. come on. Your sister needs to break it off with him, maybe. talk it through, I think?