How to introduce my rabbits?

I have a 9 month old male rabbit that I've had for about 6 months. I read that rabbits were very social animals and asked the lady at the pet store if I should get him a friend. I play with him and let him out of his cage often but I just don't want him to get lonely because I work a lot. I bought another rabbit that was 6 weeks old. He is now around 10 weeks old. I've been keeping them separated because all the older rabbit wants to do is hump the little one. They are both males. I tried introducing them slowly, but that's the first thing he does when he sees them. I want them to be able to see each other and eventually live together, but I don't know how to make him stop humping. I'm afraid he will hurt the little one. They are both very friendly and playful. Thanks for all advice!