Shit n' Ditch is the act of using the restroom at a restaurant, convenience store, drug store etc, and leaving right after you 'do your duty'. It's just meant as a pit stop to relieve yourself, and it often causes awkward stares with the employees working there, who know you're not going to buy anything. Sometimes you can't use a restroom because the facility might have it reserved for customers only. This would be considered an unsuccessful Shit n' Ditch, and you would have to find another place, quickly.
1. "Dude where were you?"
"Sorry, I did a Shit n' Ditch in the Chipotle across the street."
"Oh ok."
2. "Hey is there a restaurant around here? I need to do a quick Shit n' Ditch."
Vagina; Possibly inspired by the alleged resmblance between a pussy and an oyster. This term, along with several others, was popularized by the Bloodhound Gang song, "Foxtrot Uniform Charlie Kilo" (F-U-C-K in Phoenetics).
*Not a term one would use in serious conversation
"Cattle prod the oyster ditch with the lap rocket" -"Foxtrot Uniform Charlie Kilo"
or
Jack: Did you do her up the ass?
Marc: no, but she let me have some of the oyster ditch