This is very individual HoneyBee. Like any area, it takes 12-18 months of contiguous treatment to clear an area permanently, at a minimum, and this is provided you get enough treatment to completely clear the area every 3-4 months then continue to treat the hairs as they come in.Everyone varies about the hair density, skin history, tolerance, electrologist efficiency and skill, and a myriad of other factors. So "How many sessions" is a very particular to you number. Genital work tends to go a lot slower than other areas. There is a lot of stretching of the skin to get good inserrtions, readjusting of angle of insertion and positioning and other factors. I once had a client clock me at some astounding number while working on her face and cheeks as to amount of hair she counted. I couldnt even approach that number, for genital work.
By the way, I'm looking at your nick, are you an old client of mine?