Hmm... I used to wear black underwear because it didn't stain. But, then I found out that dyes in underwear can irritate your girly bits. I have to say, since I stopped wearing dark colored underwears, my girly bits have been less irritated.
That said, I imagine you'd want one of the fiber reactive dyes that they sell at dharmatrading since they're less likely to discharge. Some natural dyes, or the mordants used, can be pretty toxic (although I don't think logwood or walnut hulls are) and generally need to be re-dyed now and then, unless you are happy to embrace the fading.
That said, I imagine you'd want one of the fiber reactive dyes that they sell at dharmatrading since they're less likely to discharge. Some natural dyes, or the mordants used, can be pretty toxic (although I don't think logwood or walnut hulls are) and generally need to be re-dyed now and then, unless you are happy to embrace the fading.