The cave effect becomes less and less frequent and you can spend more and more time with the G-spot. Also, the contractions in the vagina become less simple squeezing and fluttering, and more a sort of reverse swallowing - a contraction that starts deep within the vagina and travels to its entrance. It feels a bit like the vagina is trying to push your finger out. Eventually (may take hours and patience and many tries) you've got nothing but these push-out contractions, and you can go on as long as the owner of the genitals wants to, and your tongue and fingers don't wear out. If you go on this long you're almost certainly going to need some extra lubricant, so be prepared.

There you have it. At least in my experience, women can have orgasms that last orders of magnitude longer and seem to be much better than those that men can have. I guess I better add a disclaimer that all of this is only one man's experience, and I could be completely wrong about the female genitals that you have. I'm not certain there is such a thing as device independence where sexual equipment is concerned. I don't think that any of the things I've advocated can do you any harm, but see your doctor if you've got doubts. The main thing is to have fun.