Butt crack意思

"Butt crack" is a slang term used to describe the visible space between the buttocks, typically when someone is wearing clothing that does not fully cover the area, such as low-rise pants or a bikini bottom. It is also sometimes used to refer to the crease or line where the buttocks meet the lower back. The term is considered somewhat informal and can be used in a casual context among friends or in certain social settings.