Yeah, I asked the doctor the same thing and he said the nerves from the baby pushing on them. Its annoying as can be, I feel your pain. I mostly get the lightening crotch and it sucks...man does it hurt but sadly I was told it's no sign of labor, just baby pushing on a nerve. Hope your rear feels better!
I suffer from the same thing... makes my face funny looking every time.
While we're on odd feelings in the butt, sometimes I feel her seemingly tapping on my tail bone... maybe she is sucking her thumb and something about the motion is felt by me down there... IDK.
Re: Lightning butt