Boy/man school teacher/student love adult

Anime exists
Story involving Kensuke's brother, Ooshiba Kousuke and friend, Setagawa Masahiro. (Both appeared in Hitorijime Boyfriend)

Ch. 1 and 5 - Okubo Shota a trainee teacher started teaching at his former high school in Third year class for 2 weeks. After break, Okubo went to get the teaching material at the top of the bookself which he cannot reach due to his short height. Suddenly, Kogure Ryo a tall student from his class helped him get the teaching references. As Okubo thanked him, Kogure suddenly kissed him and said i liked you.

From Shinmakoku Scanlations :One day Ikuta Aoi made his crush mad when he tried to confess. However, he was forced to open up to his Social Studies teacher, Shizu, and when he finds out that his crush likes Shizu he is brokenhearted. He decides to properly confess to her and, thanks to Shizu?s backing, Aoi is able to, and he reluctantly apologizes to Shizu for being rude to him. Even though things should be over, he is forced to be Shizu?s servant as punishment.

After Kei Oosawa's father died in an car accident, all he had left was his father's dear friend, Kazuma Takashina. Kazuma, who was still young, took Kei in and gave him a new home. Du

Strange rumors, mysterious legends, and suspicious corpses...
Hizuki Reiji is, by all accounts, a normal high school Japanese teacher, but he's thrust into the middle of a mystery when he moves to another town for a substitute teaching position. The woman he's replacing disappeared two weeks ago, and rumor has it that the problem child of her class, Magaki Kyoichi, was seen with a blood-stained knife the day before she vanished. The cops are on his trail, but what really happened to Sakuraba-sen

Hagiwara, who works a desk job at a college, picks Yuto up at a club. Yuto states his inexperience, and Hagiwara, attracted to his good looks and hot body, decides to show him the ropes. The two part ways, albeit reluctantly, after an enjoyable night together... only to cross paths again...! Despite Hagiwara's shock, Yuto coolly suggests they become friends with benefits! Original uploaded at Bato. Localization by : Renta (Feb 2020)