dont listen to these people about painting your plastic.
you need to use a product called bulldog adhesive promoter as your primier. it is made to work on plastic car bumpers. it will help paint stick to the plastic a lot better.
these is how you paint plastic correctly with fusion krylon cans.
1) clean plastic
2) wet sand plastic start with 400 grit and work your way down to 1500grit
3) clean plastic again then let dry
4) apply bulldog to plastic and let dry over night
5) apply light coats of fusion paint around 5-7 light coats
6) wet sand ligthly with 1500grit to smooth out any roughness left
7) apply 2-3 more light coat of paint
8) apply 2-3 coats of clear then let dry over night before you mess with it
between coats allow paint to dry but not be complete dry
paint in a warm dry area, over 70F for best results.