How do people get turned on? I mean, like, mentally, what happens?
it's all about personal preference. some people get turned on by different things because they are things which they are attracted to. Like jazlovestoskate said, it could be anything from shoes to cares, if someone likes them they may be turned on by it. Some people are attracted to body shape, butt size/shape, chest size/shape, there are many different things which people are attracted to, which causes them to be "turned on"
when they find something sexually attractive, they get turned on by it. it could be a person of the opposite or same sex, or it could be a fetish of something else (like a shoe fetish or one of the many other ones i wont mention unless you want to hear them). soem peple even get turned on by things like cars.