noun
spanking with a baseball bat
Slang term for a punishment or hazing where someone is hit on the buttocks with a baseball bat. Often associated with school sports clubs or rough humor.
部活でミスしたら、先輩に尻バットされた。
When I made a mistake at club practice, the seniors gave me a bat spanking.
あのコントでは、罰ゲームとしてケツバットが定
In that comedy sketch, a bat spanking is a standard punishment game.