After a moment of silent hesitation, he tapped once on his desk.
His stick tapped once on the hard floor.
Tap once for each day you've been in the tank.
With a cup in her hand, she went back to the room, tapped once, and walked in.
He even once or twice tapped his boot toe in time to the music.
She touched his arm bone and tapped once: she had found something!
Shieldbreaker tapped once and brushed the weapon away, along with the arms of the man who had been holding it.
The fork tapped once in agreement, and the glass of wine mysteriously emptied itself.
The leader made signs to us to pick him up and then once again tapped himself warningly on the lips.
The little finger tapped once and the index finger twice.