OK, maybe now I realize he wasn't necessarily supposed to be a flasher--perhaps he was meant to be more akin to... an inept drug dealer? an unsavory knockoff Rolex salesman?
But really, a shady character luring you over just so he can open his trenchcoat to show you something? You can see how I remembered him as a flasher.
Apparently his name was "Lefty," and he's absent from the current incarnation of the show, and for good reason. He was always approaching the other characters and trying to get them to buy whatever letter happened to be under his coat at the time. Would you like to see his D? Maybe a little T and A? Fancy a nice F? It's easy to see how Lefty could be rated X.
When Lefty asks you "Would you like to buy an O?," it's best to remember that that's only legal in the state of Nevada.
Buy Sesame Street: The Muppet Alphabet Album, Vol. 2