Also, if someone could also let me know which DVD set it is in (if it’s out), that would be great.
All I remember is Stewie teaching a kid how to play the piano, and he has the keys wired up to shock the kid if he plays wrong notes. Also. he states that he would rather be teaching bassoon, so the scene cuts to a girl over a pool with an alligator (?) in it, the rope lowers when she plays a wrong note. 
A good friend of mine plays bassoon, and hasn’t seen this yet. I’ve been telling her about it, but I can’t find this episode, nor do I even remember what the entire plot of this episode was to begin with. Please explain!