Doubt it's of any help, but i felt the need to contribute anyway;

as far as I'm aware, most of the common Japanese words for such things come directly from the English - words like "sekusu", "fakku", "kisu". The word for impregnate, interestingly enough, literally comes from "to imbue with life".

I've definitely heard of people having issues with the Japanese word for..um.. girl parts... sounding too much like far more everyday words. But anyway.