expression, godan verb (-su)
expose one's thighs; bare one's buttocks
Literally 'to put out one's thighs'; used for revealing the upper legs, and by extension can refer to exposing the buttocks, often in a risqué or embarrassing context.
彼女は短いスカートで太ももを出していた。
She was exposing her thighs in a short skirt.
そのコメディアンは舞台で太ももを出
The comedian bared his buttocks on stage to get a laugh.