The catcher is not a leaning post

[Mountaincoach]

Rant warning. Fed game. I realize there's going to be inadvertent contact between the PU and the catcher quite frequently, but when the PU decides to put his hand on my catcher's back during every single pitch and then give a forward push when he blurts out his call, we have a problem. She complained to us, and we tried to quietly ask him to stop. He was irritated, but said he'd stop. But he resumed the practice by the end of the game and certainly through the JV game. The JV catcher told the varsity catcher "It was worse than you warned me about. He literally pushed me forward." Both of them told us a few dropped balls were due to his contact with them. The catcher has enough worry about. She doesn't need that. And this guy was young and fit. He wasn't somebody who needed a crutch. Is this an accepted mechanic? What's the best way to approach this if I see it again? If it happens again, I might stop the game and embarrass the hell out of him. Imagine if one of the parents decides to tell him "Keep your hands off my daughter!!"