One method used to awaken from a dream within a dream is called a "kick", which is the sensation of falling, hitting water, or a sharp jolt that can startle the sleeper awake. It startles the dreamer out of their sleep. A kick is usually performed on one's sleeping body, not one's body in the dream within the dream; however, in order to wake a sleeper when using a sedative that allows shared dreaming within multiple-level dreams, only synchronized kicks can create enough impact to wake a sleeper. When dreaming three or four levels deep, synchronized kicks require the sleeper to experience a kick on their bodies within the innermost dream, and on all dream levels where their body is sleeping. Thus it becomes increasingly difficult to synchronize kicks and requires significant planning. Although, due to the time-dilation caused by dreaming multiple levels deep, a kick that occurs instantaneously in a higher level will last longer in a lower level, thereby making it easier to synchronize a kick.
Playing a musical cue in the ears of a sleeper is an effective way to warn one of an incoming kick and coordinate multiple kicks.