Have you tried getting her really hammered Phyriel?
Seriously.
I’d bet that her difficulty is more in the mind than a physical issue. The ass has a highly elastic sphincter, and can accomodate quite a lot. As a rule, it can easily accomodate greater length and is at least equivalent to the vagina in terms of expansion (short term anyway).
What happens is people assume it will hurt and tense up - bracing themselves. That tension brings on the very discomfort they fear. Spending time on her is great, as is gradually putting fingers in, one at a time.
But also get her drunk. :)
I’d even suggest that you lie on your back and let her control it for a while - no thrusting, just let her do it.
There’s a book called Surrender (I think that’s the title - I’m using my Treo so I can’t easily look it up, I will later), that talks about this.
If she’s already had negative experiences it will be a harder sell. You have to persuade her and kick up the romance a notch or two.
Anyway. size, in this case, is an intimidating factor, but not an insurmountable one, in my opinion.
I’d say get a butt plug and get her to experiment at her own pace. :)
Before: I'd like to show you something I'm very proud of, but you'll have to move real close.
After: I\'d like to show you something I\'m very proud of, but you guys in the front row will have to stand back.
God gave men both a penis and a brain, but unfortunately not enough blood supply to run both at the same time. - Robin Williams (: