In this paper, we propose ScenThread, a controllable threadlike olfactory display that could be woven into textiles, creating a localized scent release on a flexible surface. ScenThread comprises a tubular PTFE scent reservoir, a lightweight and non-vibrating piezoelectric pumping system for delivering the scents, and a permeable silicone tubing to diffuse the aroma, as well as a heating module using conductive yarns for accelerating the scent release. ScenThread can be refilled and reused multiple times. We articulated the mechanical design of ScenThread and the pattern design of the heating module, smell intensity and multi-scent release. We conducted a preliminary study by testing the scent releasing performance through maximum smell distance and the duration time. We envision that ScenThread could integrate into a wide range of textile-based items in daily life naturally, seamlessly, and artistically.