How do you like the idea of answering your phones by shaking your wrist? Futuristic, maybe? With the Galaxy Watch 4, you can enable gestures to answer and reject calls by shaking your wrist.
Open the Wearable app on your phone to activate gesture control, navigate to Watch settings > Advanced settings > Gestures, and toggle the buttons for both options.
At the same time, you can tap on the options to see the correct way of shaking your wrists.
Source : guidingtech.com