To urge or prod someone into action; to push someone to do something (figuratively, by scolding or pressuring).
上司は締切前に部下の尻をたたいて仕事を進めさせた。
The boss prodded his subordinate to get the work done before the deadline.
そろそろ尻をたたいて企画を完成させよう。
Let's give ourselves a push and finish the project.
母は宿題をしない子に尻をたたいて勉強させた（比喩的表現）。
The mother pushed the child who wouldn't do homework to study (figurative expression).
To spank someone — literally hitting someone's buttocks; physical punishment or spanking.
子どもが危ないことをしたので、親が軽く尻を叩いた。
Because the child did something dangerous, the parent lightly spanked them.
昔はしつけのために尻を叩く家庭も多かったが、現在は議論がある。
In the past many families spanked as discipline, but today it's a matter of debate.
先生が悪ふざけした生徒の尻をたたく真似をして、注意を促した。
The teacher mimed spanking a mischievous student to warn them.