Train sex is a phrase of recent origin. It arose in places with overcrowded trains, especially Japan and India, where "accidental" bumping of hips, bottom and genitals developed into obviously deliberate molestation, and finally penetration.

The practice has spread to other public transport and other crowded areas such as concerts, and has spread to other countries as well. Young schoolgirls in uniforms are especially targeted.

One factor for its development included the tendency of many Japanese women to be subservient or submissive and not to complain or protest, to avoid embarrassment. Other factors were the loneliness of both the molester and his victim, and the gentle persistence of the molestor until his victim was aroused.

In Japan, a male who molests and initiates sex on trains is called a "chikan" and a female who does so is called a "chijo".
I'm so sad. I rode back and forth on the Tokyo trains all day, hoping for train sex, but I didn't get molested once!

I'm sorry officer, I was inspired by the fact that there are so many videos of train sex on the internet, and I thought I'd try it too.

Teacher, I was late for school, because someone started molesting me on the train, and I didn't want to get off at my stop, in case he wanted train sex.
by Group of Friends May 24, 2011
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Referres to a sexual position involving 5 or more people standing in a line connected to each other in a sexual way
Hey,Nick, call Cassie, shanna, joe, and eric so we can have a sex train!!
by XxX MUCH LOVE XxX ~megan~ November 12, 2007
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a girl is on the bottom and there is a guy fucking her and then there is a guy fucking him up the ass and another guy fuckng him up the ass on so on and so fourth.
cindy,john,bob,joe,and jared just did a sex train
by kalee/kristen September 9, 2006
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The sex train is the term used to define an alpha male's female follower fanbase. The sex train is a term often used by highly desirable guys to describe all the guy's options in the realm of females. Everyone on the sex train is sexually attracted to said alpha male and has or would engage in sexual activity with him.
DutchEastIndiaCo: Dude that girl is totally on my sex train

YMKS: Your sex train is empty

DutchEastIndiaCo: **winks** all aboard!

*They proceed to procreate passionately*

Guy 1: You never get pussy

Guy 2: Are you kidding, the entire female population is up in my sex train, choo choo bitch.

Guy 1: Even my sister?

Guy 2: Handed that one a first class ticket yesterday!
by DutchEastIndiaCo. October 11, 2013
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When 3 or more people hot glue the tips of their penises and inserts them into the person in front of them while the conga line dance plays in the background.
Simon-Hey Steve do you want to have a Texas sex train with me and Johnny?

Steve-No my tip is still sore from last nights

Simon-Pussy
by Bigboyyeet25 September 18, 2018
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An interesting proposistion.
Where might I find this BST that I have heard so much about?
by Chris G: Unibrowed P-I-M-P January 12, 2005
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A goat that has been trained to have sex with humans. They are sometimes taked to an orgy as a curosity and to make it more kinky. Makes a good pet for a pervert.
John's got one of those sex trained goats.
by Deep blue 2012 February 21, 2010
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