I came across it on a website and which also had an eBook that I purchased. Here is the instructions:
Instructions for using gentian violet vaginally
Wash your hands
Apply Vaseline to your vulva, outside only, if you are using to protect against dying your vulva
Put a pad or panty liner into your underwear, ready for when you are finished
Put on the gloves
Add one tablespoon of gentian violet (1 per cent mix) to the plastic container
Add one tablespoon of water, to dilute by half to make a 0.5 per cent mix – one part water, one part gentian violet makes a 0.5 per cent mix
Dilute further as you wish
If using a douche, to maximise surface area and time, try to do it lying down, but expect mess; otherwise insert douche as high as you can and slowly squeeze contents while sitting on the toilet – wear gloves!
For the tampon method, after unwrapping, put the tip of the tampon inside its applicator into the gentian violet mixture, letting the tampon soak up to three-quarters of the way up the length
Insert the tampon as you normally would
Remove tampon after 3-4 hours
If you have irritation, remove immediately – and wait a day, then dilute your mixture more, and if that doesn’t work, abandon treatment and look to the next treatments