Someone who is a big-time/extreme pervert, in reference to the fact that Pee-Wee Herman was arrested in 1991 for indecent exposure at an adult movie theater and then a decade later got charged for possession of child pornography.
Simply another way to call someone a Pervert, disgusting, weirdo, pedo, etc.
*Someone touches you indecently or acts like a weirdo towards you in a strange way or is doing something "immoral"*
"OMG! Quit being a Pervy Herman!"