With a sudden blow or impact; ‘slap’.

With a dab, or sudden contact.

With a bump; with a sudden collision. Also reduplicated and as int., indicating repeated impacts or a jolting manner of movement.

The verbal stem used adverbially: With a spank or smack. rare.

The verb-stem used as adv.: With a ‘whop’; with a sudden movement or impact; ‘bump’, ‘flop’. Also as int.