The process of multiple men ejaculating on the out side of a female Sphincter hole. The alpha male then drives all the ejaculated sundtance into the females sphincter. Like compacting the trashcan. After all the waste has been compacted, you then dump the trash by the female defecating.
"Hey Brittany, are you tired of normal, boring sex?"
"Yes"
"Well good because I got a group of buddies here that want to give you a dirty dumpster"
when a guy fucks a girl in the ass before she takes a shit. when the guy is on his way to cum he pulls out and lets the girl take a shit. then the guy ejaculate all over the shit. thus making a dirty dumpling.
Usually performed near the end of sex, the dirty dumptruck is when the women is lying on her front and just before ejaculation you take a shit on your girls back (hence the name 'dumptruck') and the girl will turn around to see what is on her back then you spunk in her eyeball
when your laying on your back facing down your girl stands over you turns around bends over standing up and she spreads her cheecks and a big chuncks of shit startfalling out ontop or your cock