When you give another guy a handjob, thinking that's how you do a Dutch Rudder. It's a fucking common mistake.
Guy 1: Dutch Rudder! Dutch Rudder!
Guy 2: Yo! Stop touching my dick, dude!
Guy 1: Isn't this how you do a Dutch Rudder?
Guy 2: You have to move my arm when I grab my cock, you vagine!
Guy 1: So what did I do?
Guy 2: A...a Comfort Rudder!
Guy 1: Fail