I have one cat that likes to ride on my shoulders occasionally. I didn't train her. She, as many kittens do, liked to climb up there. I just didn't discourage her. She's ten now and still likes a shoulder ride once in a while. She solicits it. She meows and gets into a pre jump position. If I'm agreeable, I bend over and she jumps up. If I'm not I walk away. The "ride" usually lasts only a few minutes. I never pick her up and put her on m;y shoulder. And I never show her off to visitors. I admit I tried once and she promptly jumped down and move away.
Except when it's time for a vet visit for rabies and distemper shots, I don't force my cats...it really doesn't work and is a recipe for clawed hands. I invite them to sit on my lap or cuddle by patting my lap or the place near me where I'd like them to land. Sometimes, quite often they come, but sometimes they look away. In that case I don't push it.