There are a number of very good sites on the PCG muscle and things like Keigel exercises. Just a thought that maybe her muscle tone is poor and the clenching of the PCG muscles are what trigger an orgagsm.

Another thing you might try... I've been on the LIT board for a few months now and I posted a technique that I think has helped a lot of people achieve a GSpot orgasm even when clitoral orgasms are next to impossible. Lilith has copied some of my posts into THE TECHNIQUE here on the General Sex Talk board so maybe try that and see if you can stimulate her Gspot to orgasm.

I agree with the other posts ...orgasms are NOT the only thing when it comes to maing love but thay sure are the iciing on the cake. It becomes a REAL problem when one or both of you WANTS to orgasm and there is a problem achieving that. The GSpot orgasm just may be your answer. Let us know if it works. Good luck.