Smut-ish warning!
This situation brought with it a sense of nostalgia for Mei. The train was packed with human beings to an uncomfortable degree. And like the last time they had been on a train, Yuzu took it upon herself to shield Mei from being crushed. Wedged into a corner together with one of Yuzu's arms around her waist and the other propped up on next to her head as she struggled against the mass of people, whining quietly whenever she was shoved closer to Mei. The space between their bodies was growing narrower by the second.
Not that Mei minded. As previously mentioned, Mei thought of this as nostalgic of the first time they rode a public train together. Only then, rendered vulnerable because of her fever, Yuzu accidentally discovered her weak spot.
Mei was completely lucid now.
"Wah!" Yuzu jumped in alarm. "Someone is feeling up my butt!"
"Don't worry, it's me," Mei reassured.
"Oh." Yuzu sounded relieved before doubling back into shock. "What?"
Mei shh'd her and continued discreetly touching her. She wasn't one for indulging in payback very often, but she'd make an exception this time. Or perhaps this was a reward for the protection? Either way, Mei was feeling bolder than usual. It was so packed in here it was impossible for anyone to see past shoulders, anyway. That was her logic, at least. The blood rushing up Yuzu's neck was simply adorable.
"M-Mei, what-" Yuzu's breath hitched in surprise when Mei's other hand trailed up under Yuzu's shirt to cup her bra clad chest. The arm around her waist tightened as Yuzu placed her forehead on Mei's shoulder, breathing irregular already. Mei hoped everyone was too busy being miserably packed like sardines to notice two of the sardines getting a little frisky.
When they finally got off the train, Yuzu was a very disheveled steamed lobster being led by the hand by a very pleased Mei. She didn't think either of them would be able to think of trains the same way again.