A congenital deformity in which the buttocks can open up like the shells of a clam, with anus inside as a clam would be inside clamshells.
He dropped his shorts and then made everyone in the locker-room pass out from the sight of his clamshell anus.
Free Daily Email
Type your email address below to get our free Urban Word of the Day every morning!
Emails are sent from firstname.lastname@example.org. We'll never spam you.