that feeling

[putting E to bed before day 2 of grade 1.  He came home exhausted from day 1, but now, at 8:45, he's leaping around in bed and can't stop moving.  I tell him he needs to settle his body so he can get to sleep]. 

E:  I try daddy, but I just have that kindergarten feeling.  Do you know that feeling you get, it's like the feeling you get when you're just starting kindergarten.  Do you know that one?

Me:  No, tell me more about it.  It's been a long time since I went to kindergarten.

E:  It's the *feeling*, don't you know it? [exasperated:  how can you not know this?]  The kindergarten one.  It's when you have all this energy like all in the tap inside you, but the tap is turned off, and you can't let it out, because you're sitting all the time.  And now the energy is stuck inside me, and I can't get the tap to open, so it leaks.