Your friend is smart. Understand his niche: old ugly motherfuckers, most likely divorced and angry, who fly to a certain country once or twice a year to be in paradise surrounded by beautiful young hookers. They feel young and vibrant again for those few weeks a year, and the rest of the year all they can do is think about going back. During that time they look at photos from that place, watch videos from that place, get teary-eyed thinking about their favorite hookers they half in love with in that place, they make hooker slideshows on youtube with Travelling Wilburies or Journey as the background music, they post on forums talking about p4p (pay for play, as they like to call it) and how to go about it strategically so you get the best girls at the cheapest prices with the least hassle, etc. It's an obsessive niche. I don't mind outing it because I'm sick of porn affiliate programs stiffing me so I've ditched adult entirely. But if I wanted to make a porn membership site, it would be surrounding a sex travel niche like this. Bangkok and Pattaya, Thailand are a bit played out, and there are a million sites about them. But there are other destinations with the same obsessive p4p culture.
I couldnt have said it any better. +1