Honestly any girl that does this for you would probably stick around no matter what you did wrong lol girls just don't lick your cock with this much enthusiasm and imagination unless your dicking them down well or worried you might leave her (for best BJ results create an artificial sense that both of those things might be true) for added "kick" be sure to tell each girl you date "I am never able to get off from BJ but that doesn't mean I don't enjoy them" sometimes they'll look at it like a challenge to accept. The worst case scenario is she sucks you off with enthusiasm trying to be the first to make you cum from a BJ lol... It's a win win