When a person with diarrhoea is invited into the bedroom. Said person will defecate into a milkshake glass from which the two partners will drink from. The frothy residue left on the upper lip is referred to as a "Muddy Sanchez". Popular in Mexico.
Note: Diarrhoea best drunk at room temperature, for the added hit of freshness.
Woman: Hey, how have you been?
Man: How ARE you!
*the two kiss*
Woman: Wow, nice moustache! How long did it take to grow it?
Man: Oh this? Oh that's just my Muddy Sanchez.
Woman: Your what?
Man: Oh, I was drinking some diarrhoea earlier this morning from a milkshake glass.
Woman: ...... stay away from my children.