I will say that I don't like the use of derogatory comments to describe women. When it comes to female sexuality, it seems like there are so many different terms (whore, slut, etc.) to describe the behavior. However, the same reciprocal relationship does not seem to exist for a man. Even more so, if a man was seen doing a similar behavior to two women in a theatre, it might not receive the same reaction or criticism. It's worth thinking about.
With that being said, I wouldn't want to have been in your situation either. Some people really enjoy that kind of thrill though, especially when they're in a relationship. It seems super awkward to be right next to your friend when that's happening.