When you get a random girl in the back of your plumbing truck and make her grab a hold your cable that you just cleaned a sewer main with and lick it while you hit it "plumber style".
I was downtown and this chick wanted the DiRtY pLuMbEr, so I gave it to her.
A dirty plumber is when a girl squirts and the guy sucks up the cum and spits it back on the vagina and puts his fist inside her and twists
I was at this whores house and she let me give her a Dirty Plumber
After plunging a toilet you stick the plunger on your partners face and then fuck them.
Andrea: I am sick today because Winston came over last night and did the dirty plumber.
Stephanie: Really? You got sick from that?