Anyone else have a cat that likes riding other cats?

I have a cat thats name is Twister he is a russian blue, he just turned 7 months old today is still a kitten bought him in October 2005 he was born in July. He likes to jump or ride my other two cats sometimes which my other two cats who are a orange and grey tabby do not like usually, although they all are up on my bed at night, is there anyway to stop this behavior with him if so how? or is it just normal kitten behavior that will stop if so hope it will stop soon, lol. Well my tabbys fight sometimes too but not like they do it all the time of a lot. Know kitty fighting is normal but for Twister think it is a punk way.

My 8 month old kitten likes to sit on top of my other cat. She tolerates it for a bit but the growling usually starts and leads to a wrestling match. I figure that they will work it out themselves. Nobody gets hurt and I think it is just him being a kitten and annoying the other cat.

Sophies forever tormenting Rosie by either standing on her when she's lying down or jumping on her

Is he fixed? If so, how old was he when he was fixed? Was it done after he'd already matured and sprayed for a while, or just after? It sounds like either he was fixed late, and is displaying characteristics of a male cat that is, how shall I say, interested. Either that, or he's just displaying dominance.