A beer, or any other alcoholic beverage used to chug after having performed his or her duties
"That whore sucked me up and swallowed. So I gave her a beer to wash it down. "
"Ah, a whores mouthwash."
"Yeah."
The rare term of describing how it feels to temporarily choke on your own spit mid sentence, usually some people use this term in an angry, annoyed way (In an irrational tone of voice)
Random Guy: "Steve, this morning I just got Satan's Mouthwash 3 times!"
Other Random Guy: "That sounds horrible, Alan."
When you put hand sanitizer in your mouth and make out with the person next to you
Hey do you want a mouthwash martini