These Neon trees turned out great & our Pink shaving cream paint was also so vibrant and bright.
Before you say anything about the safety of it, the glow water is made from non-toxic highlighter ink in water and realistically it is diluted so much, first soaked into water in a cup, then when you run it through the bath it is further diluted (a lot), if this doesn't appeal to you even tonic water glows.
It didnt stain anything and the washable paints wiped straight off. Dimples enjoyed washing them off with a cloth and watching them run through the water.
There are endless things to use under the black light, anything White or Neon.
*Neon Post it notes, I used these on the wall & wrote Dimples name on them
*Neon Paint, I used a green neon glitter paint & painted trees on the bathroom wall earlier that day
*Shaving Cream mixed with some highlighter ink, we used this as bath paint
*White & neon pipe cleaners
*Glow sticks in balloons
*white or Neon bath toys
Washing off the purple neon glow flowers
Shaving Cream & highlighter ink = Bright Glow Messy Fun