Where a female lays on her back while her male partner proceeds to have sex with the female partners breasts. During the back and forth motion (Similar to that of a STEAM engines wheel cranks) the male proceeds to defecate, leaving a shit smear track, much like a train track, leading all similarities to coin the term "Cleavland Steamer" intended to allude to a Cleavland Steam Engine.
"I knew it was time to give Miranda her cleavland steamer, when she said 'All Aboard!' and I also added the obligatory 'Chugga, chugga' and 'Choo choo!' noises all the while.'
After ingesting fecal matter, one regurgitates the contents of their stomach into the the mouth of another willing (or unwilling) participant.
My favourite part of 2girls1cup is when the one girl hits the other with the bird feeder. I came so hard.