how do i teach my dog?

A lot of hard work!

LOL a neutered male will not "hump" your leg. Our rat terrier jumps onto leg without "humping" for attention.

Unless your dog is neutered, I have no clue why you would want to teach it to hump.

You don't. Unless you want someone to give your dog a swift kick in the ribs.

There is no need for a dog to have bad manners just because their owner either has bad manners or is completely stupid.

You do not teach your dog bad manners. It sounds as if the dog has more sense than its owner!

"Additional Details

i meant to say too stop humping people's legs long day at work"

In that case, you teach him an acceptable alternative behavior such as to sit. Then, once he knows that behavior and you've trained it in various locations and levels of distraction (starting with no distractions), you reward the wanted behavior and correct the unwanted behavior.