(人)のおしりをひっぱたくsmack someone's bottom: (人)の尻をピシャリと打つgive someone a smack: (人)に平手打ちを加えるgive someone a kick in the bottom: (人)の尻を蹴とばす、(人)を乱暴{らんぼう}に急かす、(人)をしかる