How to get out of the friend zone?

I'm in 8th grade, and he's in 9th. We're extremely great friends (i.e. we can do anything or say anything around each other and will never think what the other person says/does is awkward or weird, we love speaking to each other and always hug, have a billion inside jokes, etc.). I'm not sure if he likes me, but every time someone sits in my spot (which is next to his) at lunch, he either makes them move or offers for me to sit on his lap instead. He stares at me whenever we're in the same room, but I'm talking to someone else, and vice versa. How do I get out of the friend zone, and ask him out? If he really doesn't like me, which there's a possibility, it would ruin our already great friendship I'd rather have than asking him out and risk making things awkward.