A coyote sandwich is a used, rolled and tied sanitary napkin thrown into a public restroom trashcan. It is often eaten by wild animals that get into the trash cans or by desperate homeless people starved for protein.
My friend Pete used to work for the forestry service and he had to clean coyote sandwiches out of the trash.
That point in a relationship at which people engage in oral sex hence applying their faces to the other's home bases.
Me and Sarah? We got to face base last night. Now we can change our relationship on Face Book to face base.