crotch neck
An ill-defined region of the male pudendum which serves as a transit depot -- or toll plaza if you will -- for all manner of venereal diseases. When stimulated the crotch neck vibrates violently, changes hue, and develops mucusy lesions. Do not socially interface with anyone you suspect may possess a crotch neck.
His crotch neck gleamed, glistened even in the light of the crescent moon, yet stank of unknown quantities of putrid anal discharge.