My DS is 7.5 months old and the last 2 days he’s rocked himself back and forward a number of times. He’s done it in his highchair, in my arms whilst I’m holding him and in his jumperoo. It’s quite scary to witness as I’ve not seen any other babies do it. My 3 year old didn’t do this.
He’s also a really quiet, placid baby. I’m worrying there is something wrong with him.