Train Bidet

A term used to describe washing your genitals on a train using a bottle of coke and mentos after receiving fellatio from an unsavoury character such as a cheap hooker or toothless vagrant (the two are not mutually exclusive).

To use a train bidet one stands oneself above a bottle of coke so that the spout it pointing towards the groin. After removing ones pants, one then drops a mentos into the bottle allowing the foamy goodness to cleanse ones genitals.

"Hey Bernie, why are you late for work?"
"Well Bob, I was on the way to work when I took the opportunity presented its self to have Shazza give me a blow job"
"Shazza, the toothless prozzie? Tell me more, Bernie."
"You see Bob, after such an incident I felt I needed to wash off but as the lavatories were out of order I decided a train bidet was the best option. My genitals are truly minty fresh now after my train bidet but the time spent administering it has made me tardy for work."