When you're girlfriend is hungry for a sandwich, you make her one, with extra mayo...and begin to jerk off. When you are a mere 2-3 pumps away from climax you put your dick in the sandwich which contains boars head cold cuts and extra mayo, and you give her a bite while holding the sandwich together you pump into it, thus 'blasting her' with a combination of semen & hellmanns mayo. Bring out the hellmanns & bring out the best!!
This guy at my favorite jersey deli counter said they were out of mortadella, so he made me a great mayo blaster sandwich and it was too salty!!