not true, Manic Panic stays in my hair a long time. But everyone's hair is different. Some people's hair takes better to one brand, while it doesn't take well to another. For instance, Manic Panic is the only kind of that color that comes out really nice and stays a long time in my hair. Therefore that's the brand I've been using the longest(on and off for about 11 years!). Punky Color has nice colors, but barely lasts in my hair a few weeks. I used to be able to find a brand called Fudge that lasted well too, but the place I got it from stopped carrying it and haven't been able to find it since.
OP:I just dyed my again this past summer with Manic panic. I mixed together Cotton Candy Pink and Red Passion to create my own color!
I bleach out my hair a few days before I dye it:
then when I go to do the color, I put it on early in the day and leave it on for as much of the day as I can, wrapped in saran wrap. Then rinse it out. I mix leftover color with some plain shampoo to replenish the color as needed.
ETA: I buy my Manic Panic either from Sally's Beauty Supply or from the Manic Panic website since no stores carry a decent selection of the colors!