Would this have turned him on, and given him a hard on? how can I tell?

he said it feels good when i run my fingers over his torso like i'm tickling him, but lighter. I played with the hair on his chest and below his belly button, kissed his neck and chest, and ran my hands over his back shoulders and arms. I even played, just a little bit with his nipple. But he never really did anything to make it seem like it was making him feel good in that way. (we were just cuddling, more innocently at the time, tho he did have his shirt off). His pants had a loose lump at the zipper, but it looked like it was just the zipper, and it has that lump a lot, even when we arent doing stuff anyway. And how can I tell when he has a hard on, when our pelvic areas are no where near touching each other?