You can observe further? But other than that he sounds like a normal baby. Probably don't read too much into it whenever he closes his ear unless he seems distressed
Your baby probably discovered a new skill so he will keep doing it until he is bored of it or stop when he discovers another new thing. It’s normal.
I think sometimes babies do such actions only because they realise that they could do something, so they keep doing it for a while
Sometimes babies keep practicing new skills.