When a tranny and a tranny get into bed together and mash the improper parts together to create a 'happy train' The name comes due to the train aspect of people being pleasured with one tranny being pleasured (likely from behind) by another tranny.
Marcy walked into a room so see her sex changed son on a happy train with her transgendered boyfriend.
by Bunnny1022 May 15, 2020