bone train 

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."

bone train by valme February 16, 2006

Bone Train 

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!"

Bone Train by Gino D March 16, 2008

Bonebrain

Someone on a MTS bus, who drove pass your stop

“You missed my stop ya BONEBRAIN!”

Bonebrain by BananaHead88 June 6, 2021

Bonertainment

A portmanteau of Boner and Entertainment. Something that is both sexually arousing and entertaining.

Watching the women's tennis, I became aware of bulging in my pants, I then realized I was watching Bonertainment.

Bonertainment by hemordroid March 21, 2017