In a bowl, mix together flour and water until smooth. Try to not have any clumps because they will probably clog the squeeze bottle.
Add in the Barbasol shaving cream, mix until combined.
Add in the desired food coloring, the more drops the stronger the color.
Pour mixture into a ziplock bag or disposable frosting bag and then squeeze the mixture into the squeeze bottles. I attempted this by just spooning the mixture into a funnel at the top of the squeeze bottle. It was a no-go. Too thick and light to be able to work its way down the funnel.
Place the cap on the squeeze bottle and send your kiddos outside to create.