Quoting Ƙillingℬird:" He is just precious. I'd bring it up. But I wouldn't say it's a huge worry."
Quoting JessieLeeAnne:" LO was rocking back and forth just before he started crawling. It is perfectly normal! "
Quoting bananapancakes:" He's been doing the rocking back and fourth thing for about a month. He just started balancing himself sitting up a few day's ago."