When I began using "toothsoap," I had some homemade bar soap not all vegetable origin, and I had some of Dr. Bonner's liquid castile soap from almond oil. Even though Dr. Judd had said no to liquid soap, I felt more comfortable with it. The next day, I bought some Kiss My Face olive oil bar soap; its only ingredients are saponified olive oil, water, and sodium chloride. In few weeks, I hope to have my own batch of soap ready.
After brushing have you rinsed with salt water? Also, you could try rinsing with 2 - 3 drops of an extract flavoring such as anise, mint, or vanilla in some water.