Knowledge about materials is a fundamental element in product design education. It involves learning engineering concept about the technical properties and selection tools. More important, this concerns developing a sensitivity to the sensorial and experiential qualities of materials. We propose Material Tinkering as a practical and creative approach to develop this sensitivity through experiential learning. Integrated with envisioning and abstract conceptualization, it leads to richer and more complete projects. The paper uses a case study. This case is an experimental educational activity applying the tinkering approach to self-produced materials, i.e. DIY materials. This method fosters students' creativity and educates them to understand, evaluate, and design the experiential, expressive, and sensorial characteristics of materials, i.e. the concept of Materials Experience, Tactual Experience, and the Expressive-sensorial dimension of materials. In conclusions, we suggest strategies to facilitate Material Tinkering.