The sexual act in which the male bangs the female in the doggie-style position and upon ejactulation, releases his semen between her butt cheeks and mashes them together, thus creating a medley resembling that of a mayonnaisesandwich.
That bitch didn't want me to cum on her face, so I gave her a mayonnaise sandwich
When something doesn't sit well in your stomache, when it doesn't taste right, when you can't face eating/drinking something because you feel i'll or for whatever reason
After last nights drinking mission this afternoons pint is going down like a poosandwich