From TV Guide, this week 1977: "Has The Fonz finally met a girl he can't handle?"

Yes. I don't believe Fonzie (or any man) will be oiling this Leather any time soon.

Besides, The Fonz wouldn't fuck that one with Potsie's dick.

11/13 add: I Googled "Potsie's dick" to see if I was the first to virtually conjure this appalling vision, and lo and behold got 73 results. Apparently there's quite a pornified "Happy Days" fanfic movement out there, mostly gay-themed. "Happy Days?" I mean, I could see queering up "The A-Team" or "Dukes of Hazzard," maybe even "Knightrider," but "Happy Days?" Does anyone really want to read about Al cornholing Arnold? Or how about Laverne and Shirley doing the "Mallachi Munch" on Joanie?

I believe, in any case, that I am the first to use Potsie as punchline when positing a situation in which one would not wish to engage in intercourse with an unappealing woman such as to preclude the act even in the case of supplanting one's own penis with that of an inferior.

Malph would probably work too.