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1.
When a man is fucking a woman doggystyle and "accidentally" slips his penis into the woman's anus, and she responds by turning her head around, arching her back, and making a sound similar to a dolphin or porpoise - "eeee! eeee!"
Dude, last night I tried to slip it in Katie's ass, and she totally started porpoising - it was hilarious.
by GangstaPornBitch February 09, 2008