You're not very nice to the middle one

In one episode, Alvin becomes a music teacher and arranges a parent-teacher conference when Simon dares to suggest that the teacher actually teach something.

Alvin says to Dave "I understand you have 3 kids and you're not very nice to the middle one".

Alvin is obviously referring to himself. Interesting that he's the middle child in the 2010's show when he was the oldest in the 80's cartoon.

There was an episode of the 80's cartoon where Alvin finds himself home alone and remarks: "I'm alone? I've never been alone except for those few minutes before Simon was born!"