We present Olly, a musical textile tangible user interface (TUI) designed around the observations of a group of five children with autism who like music. The intention is to support scaffolding social interactions and sensory regulation during a semi-structured and open-ended playful activity. Olly was tested in the dance studio of a special education needs (SEN) school in North-East London, UK, for a period of 5 weeks, every Thursday afternoon for 30 minutes. Olly uses one Bare touch board in midi mode and four stretch analog sensors embedded inside four elastic ribbons. These ribbons top the main body of the installation which is made by using an inflatable gym ball wrapped in felt. Each of the ribbons plays a different instrument and triggers different harmonic chords. Olly allows to play pleasant melodies if interacting with it in solo mode and more complex harmonies when playing together with others. Results show great potentials for carefully designed musical TUI implementation aimed at scaffolding social play while affording self-regulation in SEN contexts. We present a brief introduction on the background and motivations, design considerations and results.