You can find this product at salons and stores that sell professional products. If you have trouble finding it, you can ask your stylist to order it.
It's totally non-damaging and adds pigment, and takes 15 minutes. Just don't forget to wear gloves and watch out that you wipe up any errant mousse right away as it is so full of pigment it really stains fast.

Goldwell Soft Color
Goldwell Soft Color Foam Colorant reviews - Makeupalley

6RB might be perfect, or 4G. You can mix these shades easily as well.

I keep suggesting this because it really is so very good, and so many people have no idea that a product like this even exists.
Originally Posted by SusieSuze
Great tip! I wish I knew of this before I colored. My hair is darker now than I wanted it to be so should I wait for it to fade some or will the color mousse make a difference on dark hair?

I'm definitely gonna order this and try it. Now just trying to figure out which color to get. Thanks SusieSuze!!!!
3a/b, fine texture, low porosity, normal elasticity, mod-CG 7/11/11

Poo: KC Come Clean, SM Moisture Retention
CO: CJ Curl Rehab, CJ Argan & Olive Oil, Renpure Argan Oil, YTCucumbers, Sevi Pumpkin
Style: AIF, HESMU, Biolage gelee, KCCC
LOOB for second day hair

Like BS/ACV rinses, limit protein/humectants.