My approximate thought process when I first saw this: "Well, Miyo's easy enough to find, and I'm guessing that's Asahi right behind Mahiro there, but they're not the type to prompt Mahiro's thought bubble. Momiji would be the type, and she's tagged here too, but wher-- Ahahahahahahahaa." Good enough to tag when you see it?

Alanis, squished behind a crowd of passengers

Alanis_the_Evoker said in comment #2630657:

My approximate thought process when I first saw this: "Well, Miyo's easy enough to find, and I'm guessing that's Asahi right behind Mahiro there, but they're not the type to prompt Mahiro's thought bubble. Momiji would be the type, and she's tagged here too, but wher-- Ahahahahahahahaa." Good enough to tag when you see it?

Alanis, squished behind a crowd of passengers

I don't get the joke, I see her but I don't get it

Doodle128 said in comment #2631012:

I don't get the joke, I see her but I don't get it

Well, look at where Momiji is (which took me a moment to spot), and remember:

Mahiro thought:

Someone's touching my butt...

Also, in case it wasn't clear, my first comment was about me figuring it out.

Alanis, run over by a train