Sexual act named after the tunnel which connects Windsor, Ontario, Canada to Detroit Michigan. In it a man has anal intercourse (or HRA, hot rear action) with a 19 year old girl in the alley behind _____ (insert name of Windsor bar here).
It should be noted that 19 is the legal drinking age in Canada.
“Hey bro, where you been?"
"I just fucked that drunk american girl in the ass in the back alley!"
"Ah, you just took a detour through the Windsor Tunnel my man!"