Bodily fluids associated with the menstruating body are often disregarded in the design of menstrual-tracking technologies despite their potential to provide valuable knowledge about the menstrual cycle. We prototyped a finger-worn sensor that measures vaginal fluid conductivity, which fluctuates throughout the cycle, and brought it into conversation with people through two speculative workshops (18 people), four fabrication workshops (17 people), and a deployment study where participants brought the sensor into their daily lives (7 people). We unpack that taking a material and sensory approach to intimate tracking nurtures a feminist way of sensing while creating tensions around how we want to know our bodies—tensions around how, where, and when to touch the body, hygiene, data storage, interpretation practices, and labor. With epistemological commitments to feminist materialist and posthuman theory, we invite designers to embrace these tensions.