When during oral sex, the ejaculate is so voluminous and forceful that it completely fills all sinuses in the skull, exiting forcefully via the nostrils, possibly ears, and in the rare case, eyes. So named for the both the resemblance in sound and the similar way that porpoises exhale via their blow-hole.
She made me sperm so hard, I ended up giving her a gargling porpoise. She really sounded like one, too. She had to see a ENT doctor.
by Mountin Merl March 03, 2007