How should I apply the shampoo to get an even result without staining my skin or bathroom?

Wet hair thoroughly, then squeeze out excess water so the shampoo can foam properly. Dispense a generous amount — the 40 ml tube is designed for one to two full applications depending on hair length and thickness — and work into a rich lather from roots to ends. Massage evenly to distribute pigment; the foam is the carrier that prevents blotches. Leave on for 3 minutes for a sheer sheen, up to 10 minutes for maximum deposit, but do not exceed the time recommended in the leaflet. Rinse with lukewarm water until it runs completely clear; any residual foam can transfer color to towels or pillowcases. Wear gloves (the tube usually includes a pair) and apply petroleum jelly along the hairline, ears, and neck to avoid skin staining. Wipe any splashes on tiles, grout, or acrylic surfaces immediately — the pigment can set on porous materials. Follow with a color-safe conditioner, but skip heavy masks or oils for the first 24 hours to let the coating stabilize.