1- A vagina which memes a pile of rotting cabbage. see also: blue waffle and bumtang
2- A slutty female which you keep around for sex but whom you have no respect for and can ditch easily.
3- A woman who is attractive when found due to an amount of foundation large enough to build a skyscraper on top of, however the female will likely later found to be quite skanky
1-
A: hey man that chick you were with last friday, you ever get anywhere with her?
B: No man she took her panties off and she had some mad waste-gash
2-
A: dude, that waste-gash you've got back home is starting to smell funny you should get a new one.
B: I hadn't noticed to be honest but i guess you're right. Do you want to go find a new one at the mall?
3-
A: Dude you were totally hitting it up with that chick last night at the club, you tap that?
B: Yeah man but i woke up and she was a total waste-gash.