This story has:
An awkward, relatable main girl who actually discovers she’s gay af, a cute genki girl love interest, meaningful gazes between the two, “you’ve got something on your cheek,” enamored hair touching, a successful confession, sex, and on top of that, they go to the sea and it’s not for some angsty reason. This might be the quintessential yuri one-shot.
Side note, when Shiina used that “I would date you if I were a boy” line, I was honestly pretty worried their love would turn out unfulfilled considering the drama tag. Luckily, Mako was quick to the draw and made this one of my favorite one-shots yet.