Ok, I think I can safely say he is not a stallion. I guess we'll just have to put up with his studdy behaviour. I've just found out by researching his brand that he was a breeding stallion some years ago which could be why he acts studdy. He may not have the equipment anymore but he just remembers what he did when he was a stallion.
When I bestride him, I soar, I am a hawk: he trots the air; the earth sings when he touches it; the basest horn of his hoof is more musical than the pipe of Hermes. ~William Shakespeare