DOWNLOAD THIS APP!
If you have been in an awkward situation where you would like to make a discreet exit, then the Tickle app may prove to be useful. Once you have downloaded the app, you can choose to switch it on or off. When you want to make an exit, simply "tickle" the phone. The app will trigger a phantom phone call and you can excuse yourself politely. The app can detect a wide variety of "awkward" gestures that the user makes, and is highly sensitive as it detects movement even when the phone is in the user’s pocket. It also predicts when and around whom awkward situations arise, before adjusting itself accordingly.
... Tickle is currently in its beta testing stage and is made for iOS devices. You can try it out here.