If you’re more popular than the average individual, then you probably get barraged with iMessages and other notifications as you sleep and throughout the day. iOS automatically stacks these missed notifications on your Lock screen to be reviewed later, and you can clear them individually or all in one fell swoop with a 3D Touch gesture.
Apple’s 3D Touch implementation in this regard is neat, but it’s not perfect, and it’s very much a two-step process. A free jailbreak tweak called LSPullToDismiss by iOS developer SparkDev reduces the number of steps required to clear all Lock screen notifications at one time, and it feels more natural than a 3D Touch gesture would.