This is Tucker thinking about birthdays, specifically how he thinks he will have a birthday in two weeks. He knows his birthday is in September, and so there's a great stretch of dialogue that goes something like this:
[Talking about his birthday being in September]
Tucker: is there a sock in Socktember?
Us: No, there's no sock in September.
Tucker: I think there is a sock in Socktember.
I'm not sure if anyone except the grandparents will watch this whole video, but it's Tucker enthusiastically singing a lot of songs (actually, trying to sing every song he knows)... don't worry, I didn't post all of them.
