I notice when my boyfriend and I play around he gets at least a little if not very hard. He'll just be tickling me and I'll notice it or when he lays on my chest and I give him random peck kisses on his forehead or head. Why is this arousing? He always has a playful lovey dovey cuddly attitude when we do this not a sexy attitude. Sometimes he'll try to cover it by putting his arm in his lap so I think it's unintentional or a little embarassing to him.