[williebfree]

As long as it does not interrupt "the flow of the game" it is acceptable. Many times you have substitutes entering the game and there is ample time for a "quick" high-five.

As the administering official (lead), you should be able to get them keep them "in the game" and not cause a delay by simply stepping into the lane and verbalizing a forceful, “Ok, here we go! We have one throw.” Then prepare to administer the ball to the shooter.

If the celebration becomes a habitual and prolonged and DOES interrupt "the flow of the game", I would give the verbal warning for delay.