やめなさい、お尻をぶちますよ。

to stop (an activity); to cease; to discontinue; to end; to quit; to cancel; to abandon; to give up; to abolish; to abstain; to refrain

to do

honorific/polite/humble prefix

buttocks; behind; rump; bottom; undersurface; bottom; last place; end; consequence

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to hit (a person); to strike; to beat

indicates certainty, emphasis, contempt, request, etc.; used when calling out to someone; used to catch one's breath or get someone's attention; yo!