Having been there before, the first instinct is basically what he did; a nervous giggle then the arm swings out to push her back, which depending on the chick, she might just pull it firmer into her nani n push up harder.
All while looking around at the people around you like "ayo you seeing this right?" as you try to move away.
Idk how old dude is, but it's definitely not a good time.
Especially considering it's live streaming.