You are in luck. My nickname used to be 'the Miami Makeout King.'
In all seriousness, when you first begin kissing, don't go for tongue right away; conversely, don't leave your lips/mouth clamped closed either (i am guessing that is what is taking place here, maybe you are kissing too politely and if your lips are closed too tightly then you might be befuddling your partner.)

I have been on the other end of this situation. Woman I met years ago was and I imagine still is the 40(+)-yr old Virgin. First time we kissed I could tell she A) was really nervous and B) had never done it before. She is Vietnamese and just grew up really sheltered and prudish and never kissed any boys... she eventually improved in the kissing dept (never quite relaxed her jaw/mouth though but I won't split hairs as she was sweet n gorgeous.)

If I were in your position I would just be flat out honest and when the moment is about to unfold, tell the next woman, 'look i never learned to kiss properly, will you show me?' then, if she's a good sport and you can relax enough, *she* will do the kissing, you know, that 'chick' that you may/may not be 'banging'? = )

Anyway, if that fails -- and I am not saying this being a smartass but -- go to YouTube and watch a video of two women kissing (I am guessing there are many.)