'making an attempt' on bunt

[LMan]

Can some give some input on what constitutes a bunt 'attempt' on an unhit pitch? Leaving the bat motionless in the zone as the ball goes by? Waggling or punching at the ball as it goes by?

If the pitch would otherwise be a ball, what criteria so you use (actions by the attempted bunter) to call it a strike ("swinging")?

TIA