Contrary to popular belief, a trash cat is actually an opossum. Hobbies include: long walks dirty streets, eating trash by the sunset, and getting hit by cars in their free time
It's what you call it when someone is talking trash about another person or thing. Instead of having intellectual vocabulary, you choose uneducated slang words.
The mouth is open as wide as possible giving the penis a moist feeling, but hardly any contact. Thus creating the trash can effect of a wide opening going on your dick.
She has the lips of an angel, but the mouth of a trashcan.