It appears that learning the three fairies' abilities can cause undesirable outcomes.

Luna trolling instead of Celestia for once, huh.

Called it! Not the matchups I expected though. Ya know, Ah thought Luna would be the yokel, y'all. Ah saw it on DA or somethin'.

Hahaha, I just noticed the fuuin_no_tsue in the second-to-last panel.

e: Also, bonta_kun (or maybe moffle? I can't tell if there's a scar or not).

http://ral22.deviantart.com/art/Comic-Sunny-Days-Page-2-205055809
Found the comic I mentioned.

Where's the charm with the bird from?

The fourth yonkoma also features the mask from the_mask in panel 2 as well as the tuba charm from hibike!_euphonium