Mouth too small...

Hi all! First post here, wondering if anyone has tips for me.

I’m not the best at giving BJs as apparently my mouth is too small because my jaw is kinda locked. I don’t know how to explain but it basically clicks when I open wide and therefore my mouth doesn’t open up that wide.

So when I try to give my SO a blowjob I know he doesn’t enjoy it and he actually told me sometimes I hurt him a little because my teeth get in the way.

How can I fix this? Should I do jaw exercises? Or is there something wrong I’m doing? Cus I thought my mouth is average size, there’s nothing wrong with it, but how do all those girls with smaller mouths or bigger teeth give BJs? I’d love to hear your recommendations!