that gap between your bicep and your elbow joint that you have when you flex, to fill that better in you do this, if you have a bench you can incline you incline it a few clicks up, then lay on your stomach and most likely you have to have somebody hand you the dumbbells and then you just curl up
oh **** why didn't i think of that lol. Great info again

I have narrow biceps they are defined and look pretty decent size wise but that narrow **** is annoying. Ive been doing alot of heavy hammer curls to try and add some girth.