Don't push too hard... if theres something inside (like your finger) the pressure can be very painful.
The g-spot correspondance makes sense, because when there is anything in my g/f (ANYTHING) the sensation is even better for her.
Just dont press the belly button - thats the cervix. Just above the pubic bone seems to work the best. Push in and a little down. Watch her moan
Anyway.. anyone else?