How would I put these hair dyes in?

http://www.hottopic.com/hottopic/store/p...

and

http://www.hottopic.com/hottopic/store/p...

also would these colors show up in black hair(natural) and how long would they stay? o and im just doing a little bit in the back. How would i put them in?

How would I put these hair dyes in?

im not sure that it will show up in dark hair. i tryed to do hot pink in mine and its a dark brown but it didnt show up at all. however it was a different brand. ive heard that manic panic shows up in darker hair so i might give that a try

How would I put these hair dyes in?

I would have someone dab them into a spherical sponge and whip them at the back of your head.