RPF,
I've known a few granny panty wearing girls. To be honest, they all seemed to believe they were better in bed than they actually were. Over-compensating about what great BJs they give, how everyone chases them, etc. I think good lovemaking and good underwear selection are taught at the same time.
You should hit it, of course, as you should hit all vaginal-based living things. But you should also gravitate toward the thong wearing ilk as a rule.