[Adam]

I've seen the intentional signal used. I don't use a signal. You're going to need to go to the table to report it anyway, and actually tell the coach. A signal isn't really necessary, IMO.

Personally, I wouldn't use the X because it's not an intentional foul. I don't use the baseball "heave ho" signal, because there's no need to escalate emotions. It's a call best delivered cold, IMO. YMMV, however.