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1.
when more than 3 guys make an anal sex train. grinding in and out of each other's anus like a locomotive. the guy in front is called the conductor.. all partneers thereafter are called cabooses.
"dude, i was at that gay club the menagerie the other night and these 5 guys were having a wicked crazy bone train."
by valme February 15, 2006

Words related to bone train

anal train anus bone bonetrain bum kay penis rectal wrecker sue
 
2.
It's when someone runs into someone from behind

Or

When two people are tounching when one is behind the other, and are both facing the same way.
"ohh look theres a man boning a sheep lets BONE TRAIN it!"

"ohh look theres Griffo lets BONE TRAIN him!"
by Gino D March 16, 2008