Blow jobs with braces?

So I’ve given my bf head before but I’m a nervous jaw clencher so you see my problem when I did it he very kindly told me to try and avoid using my teeth. I’ve been wanting to do it again but I’m scared that I’ll scrape him with my teeth or that one of my molar bands(shown below) on the inside of my teeth from my braces will scratch him. I don’t know what to do help!

The little mustache looking thing is on the inside and I’m afraid title scratch it I have two of these in my mouth on opposite sides