(Strip Number 4424, Original Publication Date, 1 May 1984)
Panel 1: Now that Phil has recovered from the unimaginable horror of accidentally being called a muscle-head, he tells Michael to just concentrate on getting one clear note.
Panel 2: After a fair amount of effort, Michael finally gets a note out.
Panel 3: As Michael gasps for air after having halfway blowing his brains out of his ears, Phil tells him he is doing fine.
Panel 4: Michael tells Phil that now that he can play the trumpet, he wants to learn the guitar next. Phil does not do what a normal person would do and smile a rueful smile as he remembers being the same sort of over-eager child himself. He does what an adult in the Foobiverse would do and facepalms in baffled rage.
Summary: Given that both this and yesterday's strip baffled and angered him because he never expected a child to behave like that, it makes me wonder just how good a teacher he actually is. We could be looking at Liz with a Y chromosome.