Salem, I think you do not need any additional advise because you were able to find the right way with your girlfriend, and it's even the natural one.
Anyway, if you want to add some variety to your private life, I suggest to both of you a small jewel called MAGIC WAND. It is a very effective vibrator, and it is available on line (amazon, for instance). In my case, it was very beneficial...it is a nice option to play with your partner, and if used with moderation it does not impact the couple's intimacy at all. It is not cheap (44 $) but it's worth the price.
It works well with ethero and lesbian couples. But also when you are alone
