im going to say that alternating means that he only has/buys one plug and stretches one ear at a time, when one moves larger, the other ear gets the previous size.
2g x2 lobes, 6g left inner conch, 14g helix, navel.
Future: right inner conch, helix x2, maybe a 8g navel, 14g tongue, 0g goal size for lobes.
Retired: 12g nipples, 14g tongue, 8g upper lobes, 14g upper lobes.