The Mexican Kiss is basically a French Kiss, only there is a burrito in between the 2 people kissing, in fact, you could take the other person completely out of the equation, as long as there is a lot of sauce, tortilla, and tongue.
Tom: Hey George, is that a burrito?
Tom: Why are you Mexican kissing it?
George: *sob* Don't judge me!
Tom: Oh I'm Judgin'
George: Her name is Cheryl