I (M55) have a twin brother. We attended different colleges about two hours apart. When were 19 and sophomores, he was in a LTR with a woman that I thought was okay, but nothing special. She had a nice body and cute face, but her personality wasn’t my cup of tea. Anyway, they lived together with another guy in an off-campus apartment. One weekend I visited them. Their roommate, the other guy, was away for the weekend, so I stayed in his room. My brother had to work 3-11 shift on Saturday evening, which meant I was home alone with his girlfriend. She cooked dinner for us and the conversation was just innocent small talk. We each had two drinks with dinner but neither of us were feeling buzzed, I don’t think.
Anyway, after dinner she announced that she was going to take a shower and went into their bedroom. I sat on the couch in the living room and watched football on TV. She came out of her bedroom wearing only a bra and panties and went into the bathroom. As she was walking down the hall she looked in my direction and I got the feeling she was making sure I saw her dressed that way and was trying to gauge my reaction.