Okay, this is actually what you do if you’re being sexually harassed in any kind of public space. Draw attention to it, preferably pull away and let EVERYONE know that someone is touching you. This will not only get him to get off you but he’ll definitely think about this situation next time he wants to do something like this.
Spreading the word.
My mother used to grab the hand touching her butt, lift it in the air and shout “Does this hand belong to anybody? Anybody lost it?”
When you know how quiet and laid back she usually is, this is a pretty big deal