The origin and meaning of the idiom
Originally, this expression had a separate writing: "getting screwed". And the word "trouble" was the direct, specific meaning. The so-called machine for the production of ropes. He had a complex device in the system of strained ropes was easy to get confused, and the man caught in such a trouble, had to put a lot of effort to get out of it. In addition, getting into the tangle of ropes the trouble threatened the employee with considerable danger: if the machine got the hand, the beard, the edge of the clothing, you could get a serious injury or even death.
Gradually a trouble, like many other legacy mechanisms, out of use, was replaced by another, better equipment, and the expression remained, acquiring a fused writing: "to be trapped".
The merger of the noun with the preposition and the transition to a dialect - a natural process in the Russian language.
The modern meaning of the idiom is interpreted as "to get into an awkward, ridiculous, absurd situation, to be denounced, to get into trouble by its own negligence or inattention".
As the expression "to be trapped" has become "indecent"
However, the last time in a particular environment, the expression "to be trapped" was to buy another, rather obscene meaning. The wide popularizing this value is got because of the movie "hide and seek", a black Comedy on the situation prevailing in Russia in the 90-ies of the last century.
The film "hide and seek" was filmed by Director A. Balabanov, in 2005.
The probability is that this interpretation originated in the criminal or other antisocial medium. The total value of it has remained the same: to be in absurd, ridiculous situations, but the origin was interpreted in a completely different way.
I must say that there is no historical basis for this interpretation has not, and is nothing more than a product of someone's twisted mind.
However, with a "light hand" of the film "hide and seek" this "etymology" known idiom also went to "the people" and ingrained in the minds of a certain part of young people. Some even think that to use this expression in polite society is not accepted.
Meanwhile, the idiomatic expression "to be trapped" - it is a literary expression. Perhaps this is an inevitable process, but it is not excluded that it will soon suffer the same sad fate as the word "blue", "rainbow", "to fuck" (meaning to strike), "indecent" the significance of which years 30 years no one suspected.