A Day Before Us is an animated Korean drama of a special and sweet love story of the following four main characters; Yeo Reum, Ha Eun, Kim Wook, and Yeon Woo. (Source: AniDB)

Igarashi Futuba's new job would be great if her senpai, Takeda Harumi, wasn't so incredibly annoying! Futuba hates his laugh, she hates how big he is, and she really hates that he treats her like a little kid. Just because Futuba is short and looks young doesn't make her a kid, and just because she spends so much time with Takeda doesn't mean she sees him as anything but an annoying senpai...or does she?! (Source: Seven Seas Entertainment)

OVA released with the 9th volume of the manga.

Every girl is a mystery when you're a 16-year-old boy, but Mikoto Urabe is in another league. She carries scissors hidden in her panties. She sleeps on her desk every day. She seems to have no friends whatsoever. But none of that can compare to what happens when Tsubaki Akira decides on a whim to taste a drop of her drool while Urabe sleeps. From that moment onward, things between Urabe and Akira are never the same, and the mysterious girl slowly becomes Akira's mysterious girlfriend. Along with their friends Ueno Kouhei and Oka Ayuko, Akira and Urabe try and navigate the minefield of high school first romance and all the strange things that happen along the way.