When Heidi Klum stopped by 'The Tonight Show Starring Jimmy Fallon' last night (July 30), the stunning German model was not afraid to show the world how she and Fallon "roll" -- literally.

Like Halle Berry before her, Klum took off her shoes and met Fallon on the gymnastics mat set up onstage. As the host laid down on the mat and Klum stood over him, Fallon promised not to peek up her dress, even though he totally admitted to doing so anyway.

Grabbing each other's ankles, the two then tumbled down the mat as one giant human ball, somersaulting again and again as Klum shrieked. But believe it or not, this wasn't even the most hilarious part of the segment -- that occurred when Klum insisted on doing the "German roll," and instructed Fallon exactly how to do it.

Want to see Heidi Klum and Jimmy Fallon showing off "how they roll"? Need to see what the heck the "German roll" consists of (it's a little saucy)? Watch the video above, and get ready to LOL.