Any place where a lot of cum ends up. A funny and alternative way to call someone a whore. A part of a body that touches cum of often.
Definition 1
Boy 1: My room is so dirty cuz all the fappin i have been doin lately. My pillow and webkinz are like a cum dumpster now.
Boy 2: Thats fucked up.
Definition 2
Boy 1: Dude, that girl slept with 5 guys last night.
Boy 2: Woah! She is a cum dumpster!
Definition 3
Boy 1: She sucks dick every night bro.
Boy 2: She got a cum dumpster for a mouth.
2👍 5👎