Train is used as a deragatory term to describe the same thing as a threesome.
Kinda like a player is the same thing as a ho but ho has negative connotations.
I know a lot of chicks that have fukked 2 nikkas at the same times. One is my roommate and I had to stay in the living room while she finished with one nikka and one Blasian. It's college
Imma do it one day. I want to (a lot of women have and still want to but won't tell a man because dudes think they're better) but I'm a chicken..maybe this vacation I take to the Caribbean w/ my graduating friends
Train or threesome...as long as I'm fukking one Trey Songz and one Brad Pitt
Call it what you like