I decided to use Food Colouring, as that's all I had in the cupboard and had heard you can just soak them and stain them. I tried to do more of a tie-dye effect. I used 5 plastic bowls for 5 different colours, about 25 drops in each one. I then filled it up with hot water and chucked the sticks in, allowing them to be half covered with the stain. I left them for about 10 minutes, pulled them out and dried them off on paper towel. Then I put the unstained side back in a different colour stain and let it sit. I then dried them off and put the first end back in the original colour, and repeated the process.
Here's how they turned out!
They are still drying, but I will post my finished Brain Break sticks when they are done!!