From Vinski: "I give him the hand and tell him to back off with an
official warning."
Vinski: Be careful about your wording.
There are only four official warnings in NFHS rules: defense crossing the plane of the boundary line during a throwin, free throw huddle, interferring with the ball after a basket, and failure to have the court ready, i.e. water on the court, after a time out.
Also, whether or not the NFHS suggests that officials use a visual warning to indicate to the coach that "enough is enough" has been hotly debated on this Forum. Please refer to:
Stop Sign Not Considered Harmful