Set up a container for the reaction. You can do this by using molding clay or dough or by creating one out of paper mache. You can even purchase pre-made volcanoes from craft stores or online. However, a regular plastic bottle will suffice. Regardless, your container should form a cone with a recess at the top deep enough to hold the baking powder and vinegar. Put it on a tabletop or counter where it can safely overflow. Put down newspaper if you need to.
Use a funnel to pour the baking powder into the bottom of the recess.
Mix a few drops of red food dye with vinegar in a separate container. This addition will give your eruption the appearance of real lava.
Add six drops of dish soap if you want your eruption to have more bubbles.
Pour the vinegar mixture into your volcano using the funnel. Quickly remove the funnel and stand back to watch the eruption.