I got the black folding step-stool at my local Walmart. It is about 12 inches high. They have smaller ones available in different colors. Images above: 1) Folding step-stool in position. 2) Folded and tucked away, only two inches thick. 3) Unfold the stool. 4) Stool in position with one leg lifted, 5) Both legs up and ready to GO (of course, remember to pull your pants down :^).
The images below, from the official Squatty Potty website, illustrate why a squat toilet works so well.
Your dog and all humans -until relatively recently- naturally squat to fully relax their puborectalis muscles and thereby POOP BETTER. It is amazing to me that the modern toilet allows only partial relaxation of the muscle that prevents you from pooping freely. Despite my positive experiences with the squat position while pooping in the woods, and with squat toilets in Egypt and on other foreign travels, I never thought to try to approximate that position at home. Now that I've adopted the squat position, I cannot GO back :^)
BETTER POOPING TO ALL, AND TO ALL A GOOD LIFE!