One embodiment provides a method, including: determining a first bending angle of a flexible body of an electronic device; deriving a timing duration in accordance with the first bending angle of the flexible body; controlling the first bending angle of the flexible body until the first bending angle of the flexible body gradually becomes a target bending angle at the end of the timing duration; and providing an alert upon the first bending angle of the flexible body becoming the target bending angle at the end of the timing duration. Other aspects are described and claimed.