When you finger a chick in the steam train motion i.e crank shaft for the wheels on engine
Its done hard and with grit and determination and effort whilst possibly laughing
Nolzie: How'd you go with that chick?
Garrison: Yeah I just steam trained the fuck out of her
While having a girl under the blankets, giving you your pleasure, get her all sweaty and steamy...before ejaculating yell out "TOO TOO" then push her head down and fart in her mouth and continue to ejaculating like a steam train blows smoke!!!
Dude One: Dude my balls hurt...
Dude Two: Why?
Dude One: Cause i give that girl a steam train!!!
Dude Two: WHAT...DAMN!!