Can you tell just by looking at a girl whether she gives good head? Or can deepthroat? I am not at all talking about dressing slutty or whatever -- can you physically tell just by looking at her mouth and jaw. I have a friend and all of us are always giving her shit because she totally looks like she is purpose-built for exactly that. When she opens her mouth and sticks out her tongue, you feel like you are going to fall in!!!
I don't think so. Even if you have a big mouth, it doesn't mean you're good at blowjobs. I have a small mouth and my jaws are on the small side, but I can deepthroat really well. It's all about technique and gag sesitivity and experience.