The intergluteal cleft. Colloquially known as the butt crack or ass crack, it is also referred to as plumber's crack when partially exposed above the waist band.
1) She stared with silent revulsion as sweat droplets slithered down the plumber's exposed butt gully.

2) The butt gully requires good hygiene if a case of swamp ass is to be avoided.

3) That octogenarian nudist has a very elongated butt gully.
by Cyberfossil December 12, 2018
Get the Butt gully mug.