Mine do and I shudder sometimes. It's happened all my life. Never really bothered me so I've never looked into it. Once had a brief conversation with a friend and she said it happens to her too.
I often wonder if the weird stuff my body does, that is completely normal to me, and has been happening all my life, happens to other people.
Purposely making my ears rumble is another weird thing that I realised not everyone can do.
Anyone got any weird things to add?