Other forms: stimulatingly
Something that is stimulating is exciting or interesting. If your teacher wants the whole class to dress up like pandas because it'll be more fun to learn about the adorable creatures that way, you have a stimulating teacher and a stimulating lesson.
Stimulating things may activate the mind, the body, and the emotions in a positive way. They can make you feel more alert, engaged, or enthusiastic. Working to solve a challenging puzzle, participating in a lively discussion, or watching an informative documentary may all be stimulating activities. If seeing a close friend makes you feel happy and excited, it's a stimulating experience.