The structure and devices described herein provide an improved attachment for a peripheral device, such as a stylus, to a computing device when not in use. A stylus may have magnets contained therein that cooperate with magnets in a computing device to magnetically secure the stylus to the computing device when not in use. In addition, a retractable interlock may automatically extend from the stylus when the stylus is in proximity of the computing device. The interlock is received in a receptacle of the computing device to provide an improved attachment through the mechanical interaction of the interlock and the receptacle. The interlock is biased in a retracted position and automatically extends through magnetic attraction with the computing device.