Aspects have gained attention in the earlier steps of the software life-cycle leading to the creation of numerous ad- hoc Aspect-Oriented Modeling (AOM) approaches. These approaches mainly focus on architecture diagrams, class diagrams, state-charts, scenarios or requirements and generally propose Aspect-Oriented composition mechanisms specific to a given kind of models defined by its own meta-model. Recently, some generic AOM approaches propose to extend the notion of aspect to any domain specific modelling language (DSML). In this trend, this paper presents GeKo. GeKo has the following properties. i) It is a generic AOM approach easily adaptable to any DSML with no need to modify the domain meta-model or to generate domain-specific frameworks. ii) It keeps a graphical representation of the weaving between an aspect model and the base model. iii) It is a tool-supported approach with a clear semantics of the different operators used to define the weaving. GeKo relies on the definition of mappings between the different views of an aspect, based on the concrete (graphical) syntax associated to the DSML. To illustrate GeKo, we derive, from the Arcade Game Maker Pedagogical Product Line, a new product in which new features are woven into the Product Line models.