when you perform anal sex on a girl, then once finished you go down on her and she shits on your chin.
damn it bitch, you shat on my chin now i've got a shitty chin
this is where a guy hasn't had a shower but thinks he is going to get some, so in desperation he washes his gentitals in a the closest sink available.
the classic version of this act must be in a public toilet, mcdonalds is the best.
person A: where has matty gone?
person B: oh, he thinks he's on for some so he's gone for a big k car wash because he said his dick smelled like a scampi fry.