I spontaneously visited a female friends house one day to just quickly say Hi and met a girl there she has never introduced me to. We understood each other very good and I asked her if she wanted to come to my place and watch a movie and dinner. She really was happy that I asked her, but stated since she is from further away, she needed to sleep at my place. I told her I only have one bed, but a king-size one and if she would have been cool sleeping with me in it. Girl flirted with me and told me she would be glad to spent the night with me in one bed. Okay, pause here and think about it, what does this sound like? For me it was clear she wanted to have sex, we flirted so hard and hit it off really good, we very much liked each other and she was willing to sleep over on the first date. On that evening, she came around and we had a really good time, watched a movie, had a nice meal, girl cuddled herself into my arms. We didn't drink at all and when it was time to go to bed, she told me she had nothing to wear for the sleep over, like she didn't know all of a sudden she had to spend the night, so she stripped to her undies and came to bed. As soon as the lights went out she rolled over and started to kiss me wildly. Girl was really into it and super horny from what I could tell. We made out and at some point while the girl was laying on top of me, I grabbed her butt and touched it all over. SHE STARTED TO FREAK OUT! Hey! Did you just touch my butt? I was so confused. Girl was still on top of me with spread legs and started to scold me. She was so angry that she called somebody to pick her up at about 2am. I couldn't believe what just happened that's part of a sexy time to grab someone's butt, what went wrong? She continued to ask me why I grabbed her butt and I told her because I find that sexy during sex, but she couldn't believe it like it was something otherworldly. Some girl came to pick her up and she left, have never spoke to her or seen her since and I am still confused what happened that night.