In a bowl, mix the glue and shaving cream together. As much as you put in is about how much slime you'll have so you'll have to decide if it's enough! Put a few drops of your food coloring in.
Make 2 batches so they each have their own colors. Once the colors are blended, add your liquid starch and it will start to form.
After a minute of stirring, take it out and stretch/knead with your hands.