けつをまくる

Also written しりをまくる, ケツをまくる, 尻をまくる, 穴を捲る, 尻を捲る

Meanings

1. Expression, Godan verb to suddenly assume an antagonistic attitude; to suddenly become defiant; to turn aggressive (in one's manner)
2. to moon; to point one's naked buttocks at someone; to give someone the brown-eye

Jinuma: Japanese Dictionary · Word lists