Alice,

My girlfriend and I started experimenting with this recently after I had some fantasies on such. Ironically, she was the one that suggested it. I told her I might be interested and she came home one day with a strap-on. The first time hurt quite alot, but the whole domination aspect was pretty good cause she's normally submissive. Suggest it to your gf, the worst thing she can say is "no" :P