Finally, a practical reason to use my double bass pedal! I reversed the action of the slave pedal so I could sit comfortably on the cajon (well, as comfortable as a cajon can be when you're sitting on it for approx. 6 hours) and not have my leg in the way if I wanted to play the cajon with my hands. It worked out nicely! This page helped me modify the pedal.
This was for a women's seder on Long Island. The ensemble consisted entirely of women, about 15 of us. It was a beautiful experience!