buttocks
n. 臀部；纵剖线（buttock 的复数）
v. 用过背摔摔出对手（buttock 的第三人称单数）
例句
There were marks on his buttocks I hadn't seen before.
他的臀部有些我从没有见过的疤。
《柯林斯英汉双解大词典》
You can do this with your calf muscles, thigh muscles (front and back), chest, abdomen, buttocks, shoulders and back.
你可以对你的小腿肌肉、大腿肌肉（前面和后面）、胸部、腹部、臀部、肩部和背部这么做。
Brush buttocks with bumf before, how do you convert now to wipe the mouth with bumf?
以前用卫生纸擦屁股， 现在你怎么改用卫生纸擦嘴了?
