My wife and her sister had a girl's WEEK the year before covid, and I told my wife to have as much fun as she wanted. I was hoping she would have some kind of fun. I told her as long as she told me all about it, then anything goes. She knew I was serious. I knew that she wouldn't sleep with anyone, but if she did then she did.
My wife didn't do anything remotely exciting (she would have told me).
But her sister, the conservative prude nun-in-regular-clothes-type, got drunk (second time in her life), danced with a stranger, let him slide his hand up her dress and hold her rear end while dancing under the dress, she grabbed his package a few times over his pants on the dance floor, and she let him nuzzle between her boobs in her dress. My wife said that her secret was safe had she brought the guy back to their room.
My wife was sort of jealous that it didn't happen to her, but she said she enjoyed it more seeing her sister let loose. (If her sister had cheated and left her husband, the entire family would have rejoiced, for what it's worth.)