I have worked out how to brush my teeth without using water.
In the past I have always used pretty much a full cup of water to rinse with, but for the last few days I tried it another way round:
I have brushed my teeth as normal, but instead of using water to rinse I have used a cap of mouth wash and it worked really well.
I still get the burning feeling after the mouthwash, but have cut out the need to use water. Well pleased with myself.