Body capacitance sensor
From Opendildonics.org
A body capacitance sensor senses human proximity or touch by detecting a change in capacitance. An example is nightstand lamps which turn on or off when the metal base touched.
Teledildonics applications include measuring hand position or insertion depth on a dildo.
For general information on the concept, see the Wikipedia articles on Touch Lamp, Body Capacitance and Touch Switch.
