In this study, we investigated how users work with a tablet in a non-desk setting. While portable computing devices have enabled ‘work anywhere’, few furniture and user interface has been designed for working in non-desk settings. In a co-exploration study, participants (n = 20) performed three tablet activities (video watching, typing, and drawing) on a configurable sofa. Using multiple cushions, the participants iteratively explored comfortable sitting as well as lying postures in diverse body orientations. The result showed a variety of postures and support configurations for the comfort of working in a non-desk setting. Unlike working a ta conventional desk setting, the body parts supported each other as well as a tablet, and preferred postures were unique to each activity. By systematically analyzing and categorizing postures, we uncovered new design opportunities for furniture and interactive systems that do not deal with a traditional desk setting.