I dont understand it either. I think its like a comfort thing, a reaffirming of manhood or something
Speaking as a guy, it could be any number of things. Sometimes underwear gets bunched up or partially turned and that's uncomfortable. The British have a saying, "Don't get your knickers in a twist," when someone is acting all upset. This is because when that literally happens is IS upsetting and makes men squirm.
Another possibility is an itch.
In both cases, you are supposed to wait until you can get to a men's room where you can shut the door and have some privacy while you fix the situation.
A third possibility is that it's some kind of dance move. Michael Jackson used to have a signature dance move where he would very abruptly grab his crotch and sing "Hee HEE!" in a very high-pitched, loud shriek above the rest of his song. He was considered an excellent dancer, which I agree he was.
I know i don't see why they would do it neither.
Look at them while they speaking by cell phones))))