It seems quite simple, but I think you need to see my instruction video on how to fuck a belly button. From lubing it up, to my turn-on's/experiences belly button fucking, I think you will find this video VERY hot and helpful, If you ever find yourself with large girl, who will let you fuck her belly button. Preferably someone close to my size, as I think the bigger the girl, the better the belly button fucking.. atleast from my experience. ;)