Hands and Knees position

[Jurassic Referee]

Screening principlesas defined in the rulebook state that the screener must stay within their vertical plane. Ergo, to have a legal screen, the screener has to be standing. If the player isn't standing, you simply can't have a legal screen.

having said that, the rules also state that any player is entitled to a spot on the playing court though as long as they got there first without making illegal contact. However, a further explanation in the rules say that you also legally can't play while bending your body into other than a normal position.

Those are the criteria that we've been given to work with. If you apply them, then imo any contact caused by a player getting on their hands and knees would be illegal contact charged to that player.