This is my hair before (terrible roots wahhhh):
I then mixed some Directions Pastel Pink (i think...) with conditioner, and added a dab of Carnation Pink (a really bright pink) to make it brighter:
I then used a tint brush to 'feather' it onto the hair, to avoid a harsh line of colour. The lower I got, the more 'Carnation Pink' I added to the mix, so the more intense the pink colour became.
Once it was on the hair, I let it process for about 20 minutes, rinsed, and voila:
Just a quick warning: some colours stick more than others, blue being the main culprit... I'm pretty confident that this will wash out in about 5 or 6 washes, but if you do a blue tint, that shit'll stick around...!