Trashbarging is precisely the same as motorboating, except for the fact that when trashbarging the trashbarger places their face in the cleavage of the trashbargees ass, rather than their breasts.
I met this girl named Boston at the bar the other night and bought her a few drinks... By the end of the night, I was trashbarging Boston's harbor!
When a person (usually a female) does something really trashy and is not only proud of it but brags about it like it's the greatest achievement of their life.
She said she had a one night stand and didn't even know his name, she's such a trashbrag.