If you keep it far enough away from other rocks, it will not really jump in my experience. However i did have a piece pinch off one time when it got too big and landed somewhere else to attach...so thats something to consider i guess.
But imo, the main thing to do is place it up high if you dont want it to spread. They grow towards the light. So if you place it down low, it will crawl up every rock it can reach to get up higher (and leave "babies" behind where it started...which in turn grow larger).
hth