“Intimacy Patches” are personal devices that monitor various vital signs during sexual activity. A graphical representation of these signals is then displayed on a voyeur’s mobile phone. The patch wearer selects whether to transmit these signals to a particular individual or to the public realm via the Internet. This project can also be used in conjunction with existing mobile phone features. “Intimacy Patches” allows the user to engage in discreet exhibitionism or simply communicate intimate behaviour to a specific individual. This project offers a provocative new medium with which to explore the different boundaries that lie in sexual relationships, bringing a private interaction to a public sphere.