patience and lots of lube ... learning where the best stretch at her opening is a big help, usually you can work pushing the lower part of the vagina down towards her asshole and it will give easeir than other parts ... getting a rotation of the knuckles that allows them to get past the entrance NOT at the same time is also a help and quickly curling your fingers back into your palm ... once in there is lots of give for the width and size of the fist but getting your hand through the opening is what takes practice ... have some cone toys to let her work on it herself is also a help
to alwaysjuicy :Thanks for your advice, one problem we have is I travel for 4 weeks at a time. So home time can be limited. She has been working with large dildos up to 3" in diameter. I know she will be getting close to fisting soon. I know she will be a squirting like she never has before once I fill her pussy with my hand and that is a huge turn on for me to say the least.
What I have found to work out for me at least, is slowly build up to your fist. My guy and me have been doing this for a couple month's and he started with only using 3, and then he would go to 4 and just recently his fist. I have never cummed so much in my life than when he fists me. I also will rub on my clit, or pinch on my nipples. Hope you guys enjoy!!
Thanks Again
R