This article explores the ways in which experiential knowledge of disability is mobilised in user interviews concerning the design of packaging for everyday consumables. A review of the literature on experiential knowledge is presented to clarify its characteristics. To study its application under real-life conditions, we conducted an activity analysis of people with disabilities (PWD) involved in a design project. This qualitative method, which focuses particularly on mental processes, reveals experiential knowledge despite its tacit nature. Our results indicate that PWD spontaneously perform demonstrations to illustrate their capabilities and limitations in using products. We propose to define the demonstration of use and its implications in collaboration with designers. This embodied strategy facilitates the sharing of experiential knowledge by showing the underlying logic of actions and, concretely, how a person uses a product. This method enables PWD to evaluate the usability of products and, more generally, to raise awareness among others about disability in relation to accessibility.