There's a lot of talk these days about sentient cities, augmented reality, the "metapolis"--about how pervasive and ambient computing, combined with urbanization and the accelerating mobility of people and things, is reconfiguring inhabitance and inhabited space. Missing from this talk has been a consideration of how these phenomena reconfigure somatic experience. We are creatures of movement, specifically of rhythmic movement and of the imitation of movement. Sociality--among humans and between humans and other animals--begins with the observation and imitation of others' movements and the rhythmic synchronization of our movements--and from there our intentions and feelings--with those of others. At the base of social life stands a shared experience of kinesthetic empathy, an ongoing choreography of movement and intention that binds sentient creatures together like coupled oscillators. This we call social entrainment (Mitnahme). Today, changes in the formal properties of inhabited space are reconfiguring the spatial and temporal topologies of social presence, and with these the experience of social entrainment, at a speed and on a scale vastly exceeding previous revolutions in mediation. We are subject to a volume of social zeitgeber or entrainment cues that was unimaginable ten years ago. The result has a been a new kind of plasticity in our experience of kinesthesis and social entrainment. We have no language for talking about this, let alone probing it experimentally or addressing it through design. In this talk I offer a new take on social entrainment, one that encompasses both the kinesthetic synchronization of mood and intention and the synchronization of social rhythms over circadian and longer horizons. I discuss how somatic rhythms of rest, activity, and locomotion are becoming focal objects of self-care, notably via personal accelerometry devices such as Nike Fuel and Larklife. I suggest implications of new forms of sensorimotor and social presence for how we experience mood, arousal, attention and empathy, how we learn, and how we ascribe social statuses to ourselves and others. I draw on linguistic anthropology to propose a conceptual vocabulary for exploring changes instigated by the dramatic extension and intensification of peripersonal space. And I ask what it would mean to put kinesthetic empathy at the center of the design process.