Weird sleeping habit?

ok, its not rlly a habit, but it helps me fall asleep. so like before i go to bed for like a good 45 minutes all i do is pretty much rock my head back and forth rlly fast, and its kinda weird. but it feels rlly good, kinda like how u feel wen ur on a slow rollercoaster. y do i do it??? how did i even figure that out?