Basically, I can tell when they're having fun. Unlike women, it's harder for them to fake it. There's telltale signs, like erections, and stains on the sheets.
I aim for the 20-27 age range. I want someone with plenty of energy. But, any younger than twenty, and I find they can have a bad attitude, especially towards hygiene.
I find I can get amazing sex out of them. Especially when I let him know there's a chance of a bonus if he does a good job.
If he accepts those terms, I then go hell for leather to try and turn him on in bed. I will do things to him you haven't even seen in porn films. Whatever it takes. It's worth it, because he then feels he has to compete, in order to earn his bonus, and the fun just escalates.
I'm usually pretty honest with them. I tell them I'm not after LT. I'm traveling. I will leave. I don't tell them exactly when. Sometimes, they pretend to be heartbroken that I don't love them, but really they're just trying to manipulate me because they want to continue getting money out of me. And I like that! This isn't a serious relationship, and nobody gets seriously hurt when it ends. Everyone leaves (pretty well) happy.
I never tell anybody I know about my little dalliances while on holiday in Asia. Partly because I'm pretty sure nobody in the world wants to know. But also I'm a bit embarrassed, because it all just seems so sleazy. All the same, as long as everyone involved is a consenting adult, and as long as we're all having fun, is there any harm? Seriously?