Teethy

So, I gave my first blowjob yesterday and about 7 minutes into it, he asked me if there was any way I could use less teeth. For me that's kind of impossible because I already have more teeth than a normal person. I said sorry and that I couldn't so I just gave him a hand job instead. 
I feel really bad, he told me that the blow job felt really good but the teeth didn't hurt him much it was just distracting from the blow job. 
Is there any way that *you* guys prevent your teeth from scraping your mans dick?