Sweet toothpaste can absolutely trigger an addictive reaction. The conduit is the sweet taste buds on the tongue—it doesn’t have to be swallowed. Very sweet chapstick or lip balm can cause a similar response. For this reason, it’s wise to avoid excessively sweet flavors and stick to plain lip balm and toothpaste varieties comprised mainly of baking soda and peroxide. You can be the judge of whether it triggers you or not. Some brands are less sweet than others.