Here's a quickie. Want to learn how to give your girl better oral?
It's easy. Watch some girl-on-girl porn and study their tongue technique. Better yet, participate in some girl-on-girl porn, possibly with a camera, and get the firsthand experience.
Lastly, don't try to devour the thing whole. You might get indigestion. And she might get a new guy who actually knows his way around down there.