Mostly be afraid of lethargic times not the go go go times.....Mine do it after they poop sometimes, get a whiff of something that excites them or the wind blows right....Diggy did it last night while playing with Bella and he kept tripping and hitting his head on the wall...he is also 3 months....his butt get real low he runs like a rabbit and bobs his head up and down.....
GO PLAY WITH HER...she wants to play