I remember Spanish Fly… it was advertised as an aphrodisiac that made women super horny. The ads for the mail ordered product were on the back pages of the Playboy magazine and many men/boys ordered them in hopes that women would wanna sleep with them after taking a sip.
Of course, the “love potion” never worked but back then, they didn’t have Amazon reviews so no one knew if it really did work or not and it became this urban legend/fantasy thing, if it truly existed, that every guy wished for. That’s why Larry King could relate to the joke, because every guy that read dirty mags back then could.
It’s just super creepy to think that it was part of Bill Cosby’s comedic act back then knowing what we all know now.