Enjoying My Handjobs, but With a Question

I totally enjoy masturbation, I guess like any guy my age does. Until recently, I always stroked myself in my bed, and cleaned up my mess on my stomach. But recently, I got really horny alone in my car. I reached down and started stroking myself through my jeans, and before I know it, I had an orgasm. I soaked my pants and underwear on the left side with a good stream. To me it was totally awesome. The feel of the fabric felt better to me than lube. I now do this regularly, while driving and when I sleep at night only in my underwear. I even perform for my girlfriend this way. My question is, am I normal in enjoying this? I don't see any harm in it, and I do my own laundry.