Insert Disc 1 and start the first episode, 'Stark Raving Dad.' After the episode begins, press Audio, then press Down to cycle to the fifth audio track. This will provide access to a solo commentary by Mike Reiss not available on the extras menu. Insert Disc 2 and view the 'Lisa's Pony' episode. Press Audio, then press Down to cycle to the fifth audio track.
Insert Disc 3 and view the 'Bart The Lover' and 'Separate Vocations' episodes. Press Audio, then press Down to cycle to the fifth audio track. Alternately, listen to the third audio track in each of those episodes. Alternately, enter the 'Special Features' menu for the episodes with the extra commentary. Then, press 10.