Akin to a Cleveland Steamer, the Mississippi Riverboat is accomplished by first getting the runs, then taking a liquid shit on the neck and chest of a woman, at which point the shit runs down her like a wide, muddy river
I had enchiladas for lunch, which turned the Cleveland Steamer I laid on her into a Mississippi Riverboat
by Milfadd May 3, 2011
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This is a sexual act that is similar to the "69". The female participant is on top and holds her arms straight while servicing the gentlemen on the bottom. The male holds the females feet in his hands and rotates the ladies feet in a circular motion to resemble the propeller on 1850's riverboats.

David Wilcox's "Riverboat Fantasy" must be playing for the entire duration of the Upside down Riverboat.

This sexual position was inspired Cowboy's and Alien's which features an upside down riverboat.
So then we Upside down Riverboated all night.
by Colonel Shvatz November 9, 2011
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When a girl gives you a hand job using both hands. Fist the right up the shaft then the left....repeat. Kind of like milking a cow only there is only one teat.
My girlfriend asked me if I wanted a regular or riverboat style hand job.
by Bobby Poppe September 17, 2006
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When a man is penetrating that sweet poon poon, he fists the women right in the mothafucking ass and finds where his dick is in the vagina and starts to rub his dick from the anal canal until he cums in a furious rage.
Jerry got shit all over his hand after doing a Chinese Riverboat in a well mannered prostitute.
by The Awesome Putin October 17, 2015
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