This paper introduces JerkTilts, quick back-and-forth gestures that combine device pitch and roll. JerkTilts may serve as gestural self-delimited shortcuts for activating commands. Because they only depend on device acceleration and rely on a parallel and independent input channel, these gestures do not interfere with finger activity on the touch screen. Our experimental data suggest that recognition rates in an eight-choice selection task are as high with JerkTilts as with thumb slides on the touch screen. We also report data confirming that JerkTilts can be combined successfully with simple touch-screen operation. Data from a field study suggest that inadvertent JerkTilts are unlikely to occur in real-life contexts. We describe three illustrative implementations of JerkTilts, which show how the technique helps to simplify frequently used commands.