An idiom used to express feelings of regret and remorse, stemming from a realisation that one has willingly participated in behaviour that has led to an unforeseen and morally reprehensible outcome. The idiomatic use of eating serves to convey both the initial positive, tasteful, experience, as well as the negative, distasteful, after-effects.
Clearing the rain forest is how I make my money, but seeing locals driven from their homes has left a bad taste in my mouth.
Having an unpleasant taste in youre mouth, mostly ment as a methaphore, but sometimes literally. It can be caused either by a feeling or an actual event.
Either way, if something gives you a bad taste in the mouth it is always bad.... really bad..
Catherine said: A beating from the love truncheon left a bad taste in my mouth
A man comes home from work (working as a male fluffer) in the porn industry.
Wife: How was your day today, dear?
Man: Don't even ask, I have a bad taste in my mouth!
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.