Electric blue is the colour of blue neon signs. It is a mixture of cyan and white, but is most easily achieved using a fluorescent blue paint and pearlescent white paint for a more metallic colour. The colour is also known as ice blue. This tutorial assumes you are using acrylic paint, though most paints will mix in similar ways.
Put cyan or fluorescent blue paint in the paper cup.
Add an equal amount of white paint to the cup. Mix.
Add more white paint to the cup in small amounts until the shade of blue matches what you want.
Mix the colour with the mixing stick until the colour is even.