What should I do if i catch my crush staring at me or vice versa?

i only have homeroom with him but i cant help staring, he's like a magnet, my eyes wonder right to him. and then as soon as i look for no more than 3 seconds it's like he knows and looks right at me, this also happens in the hallway too but i always quickly look away. And today we had this embly thing and i could see him staring at me from the corner of my eye and i couldn't help it my eyes went straight to him and we met eachothers gaze for all of like half a second and then i quickly looked away. I want to know what to do next time this happens so it's not all awkward. should i smile? or hold the gaze? or what?