What is that popping???

Since around 36 weeks maybe a little earlier than that I have been hearing this strange popping sound coming from my belly. Usually when it happens my baby is moving, usually really fast. I’ve actually seen a lot of google posts about this & people seem to think it’s either the babies joints cracking to the fluids swishing around in there. My OB looked at me like I was crazy when I told her lmao. It’s like a really weird phenomenon. Does anyone actually know what this is? It is so bizzare.