Is using crayon to blend in colored pencil a good idea?

I don't know if using the word "blend" describes what I'm trying to do but basically I want the colored pencil coloring to look solid. I don't care for the little white spots the coloring can't cover. At school I asked my teacher for a colorless wax pencil to "blend" my work but she didn't have one. So she suggested that I use crayon(I believe it was Crayola), and I did. It looked like it was working but I wanted to know if that was a good idea. Any answers?