Rudd then emulated the iconic leg-crossing move that Sharon Stone performs during the interrogation scene of the 1992 thriller.

However, it didn't exactly go as smoothly as Rudd anticipated, since he didn't take his boxers waistband into account -- or what such an image would look like to Douglas, who was rehearsing his lines "like a pro."

"I should've just stopped, and I didn't, and it looked like I was basically pleasuring myself to Michael Douglas giving a monologue," Rudd explained. "He just stopped and just looked at me and said, 'What are you, a f---ing pervert?' No smiles."

Thankfully, Douglas -- who himself recreated the scene earlier this year on The Late Late Show with James Corden -- had the most down-to-earth reaction to Rudd's snafu.

Watch Rudd recall the moment in the video below.

Rudd also took on Fallon in a game of Drinko: