bare thighs; inner thigh
Refers to the exposed or unclothed thigh area. Often used in contexts describing appearance or physical contact.
She was showing her bare thighs from under her skirt.
intercrural sex
A sexual act involving stimulation between the thighs without penetration. Often encountered in adult content or slang.
That adult video had many intercrural sex scenes.
Compound of 素 (bare, unadorned) and 股 (thigh, crotch). The sexual sense is a modern extension of the literal meaning.