FlexStylus, a flexible stylus, detects deformation of the barrel as a vector with both a rotational and an absolute value, providing two degrees of freedom with the goal of improving the expressivity of digital art using a stylus device. We outline the construction of the prototype and the principles behind the sensing method, which uses a cluster of four fibre-optic based deformation sensors. We propose interaction techniques using the FlexStylus to improve menu navigation and tool selection. Finally, we describe a study comparing users' ability to match a changing target value using a commercial pressure stylus and the FlexStylus' absolute deformation. When using the FlexStylus, users had a significantly higher accuracy overall. This suggests that deformation may be a useful input method for future work considering stylus augmentation.