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.

It’s an acronym standing for Can’t Remember A Fucking Thing. It’s usually used to describe embarrassment at being unable to remember someone (CRAFT moment); going onstage as the lead in the latest theatrical performance and your mind goes completely blank (CRAFT situation); the next morning after a night when you got pissed as a fart and woke up in bed cuddling a traffic cone and a string of fairy lights wound round your prick.