What does it mean when a guy squeezes your knee?

Im in eight grade and theres this guy i really like who likes me too, but he has a girlfriend in another school. we hang out sometimes and hes really nice, not to smokin hot! one day in art cl, out of no where he squeezed my knee and I looked at him and asked him what he was doing but he didny answer me. I was just wondering if anyone knew what that means?