Definitions by Kevin Be.

mayonaise 

A codeword used for when you buddy is hooking up with an unattractive girl

As your boy is hooking up with a completely gross girl
::taps him on shoulder::
"Yo bro, lets hit up the deli, I'm getting a sandwich with extra mayonaise"

"Dude you put way too much mayo on that sandwich you ate for lunch

mayonaise by Kevin Be. February 12, 2008