We present Plex, a finger-worn textile sensor for eyes-free mobile interaction during daily activities. Although existing products like a data glove possess multiple sensing capabilities, they are not designed for environments where body and finger motion are dynamic. Usually an interaction with fingers couples bending and pressing. In Plex, we separate bending and pressing by placing each sensing element in discrete faces of a finger. Our proposed simple and low-cost fabrication process using conductive elastomers and threads transforms an elastic fabric into a finger-worn interaction tool. Plex preserves an inter-finger natural tactile feedback and proprioception. We also explore the interaction design and implement applications allowing users to interact with existing mobile and wearable devices using Plex.