Definitions by O'Byrne's Converser

Philadelphia Underpass 

When Gentleman Number 1 is getting railed up the ass by Gentleman Number 2. At some point, Gentleman Number 1 reaches under himself and sticks a finger up Gentleman Number 2's anus, thereby giving him the ol' Philadelphia Underpass.

When Craig gives me the Philadelphia Underpass, his finger smells like my ass all afternoon.

Philadelphia Underpass by O'Byrne's Converser June 1, 2011