I've always been intrigued by people who were into being on the receiving end of this. Being a) a male and b) unable to understand different mindsets from my own due to autism, it's always been something I've been curious to understand.
Well, I guess the simplest answer is just that different things appeal to different people. Fetishes can be a mix of pleasure, eroticism, danger, or even violence in some cases. I personally find a big snake wrapped around me to have an erotic appeal, but I understand it could be very dangerous so I'd never do it alone.
My snakes were always extremely mellow, but as they got bigger they also got heavier! They also had the annoying habit of refusing to cooperate. The result was that I went to no end of trouble getting a suitable model, dressed just so an posed properly before my cameras and this 15 foot nut refuses to coil around her or stay where I put him! Very frustrating! But when everything worked right it was great. 2 of my models even got snakes themselves and loved them.