This paper describes our experience in constructing a new Domain-Specific Language course at the graduate level whose objectives is to reconciliate concepts coming from Language Design as well as Modeling domains. We illustrate the course using the reactive systems application domain, which prevents us to fall back in a toy example pitfall. This paper describes the nine stages used to guide students through a journey starting at low-level C code to end with the usage of a language design workbench. This course was given as a graduate course available at Université Côte d'Azur (8 weeks, engineering-oriented) and École Normale Supérieure de Lyon (13 weeks, research-oriented).