For convenience sake, we'll simply define perversion as deviation from a culture's view
of normal sexuality.
For example, let's take the Folsom Street Fair. While actual sexual activity at the Fair is discouraged and frowned upon, the dress and overall style of the attendees gives a good clue as to their interests: leather, chains, cuffs, masks, 9" spike-heel boots, spikes, whips... You get the idea.
However --- the Folsom Street Fair being what it is --- all of that is defined as normal, at least for the duration of the Fair and within its geographic boundaries. So, let's say a guy named Lenny goes to the Fair to flyer for his friend's piercing shop. He's wearing engineer boots, black Ben Davis pants, a Toy Dolls t-shirt, and has a zipped sweatshirt (a non-hooded hoodie) stuffed in his Zo-bag, along with the shop flyers and other stuff.
In this situation, Lenny is the pervert. In fact, Lenny wishes he was still seventeen and still thought spike bracelets were cool; they would have helped a little to blend in with the crowd. As it was, Lenny attracted attention to himself by NOT being dressed in leather, chains, et. al. Seriously, people stared, all day.
Lenny's sense of humor and ability to chat with strangers, no matter the situation, saved the day. Coming across a domme being pulled in an old-school, full-size rickshaw by her sub, he asked her where the fare meter was installed: both of them laughed, and the sub said, "Mistress, I know how we could make a ton of extra money!" Lenny complimented people on their... Ahh.... Well, they weren't clothes... But "costumes" would be insulting --- this ain't fuckin' Halloween for these people, it's a big part of their lives ---
Let's just say Lenny complimented people on the custom-made, damn-pricey-looking leather apparel many were wearing. People were flattered. Many, many flyers were handed out. Overall, Lenny enjoyed himself. He did, however, turn down a couple invitations to come to peoples' houses after things ended for the night: The invitations were from very large hairy gentlemen in leather thongs, motorcycle boots, and little else. Lenny thanked them and explained he had to meet his girlfriend later that evening. (Lenny was single at the time, and the only "girlfriend" he had was at the end of his left wrist. So it wasn't entirely a lie.)