After they played with the shaving cream for a while, we placed a piece of white cardstock onto the shaving cream to make a print. This creates a pretty marbleized print (after you scrape the shaving cream off the paper).
The girls enjoyed the shaving cream so much that we did a variation of the same activity the next day. This time we used powdered tempera paint instead of food coloring. It turns out that blue and yellow don't necessarily make green!
We didn't make any prints this time. They just enjoyed the sensory experience of smearing themselves in shaving cream and then washing it off in the lake.