Digging To Survive: I Can See Hints - Chapter 581 - Carmela Viper

Our straight (?) bottom woke up ten years into the future and found himself on the bed of his childhood friend… At the start, the bottom was shocked to his very bones, but he soon quickly accepted this premise and found the whole situation to be rather amusing. Precisely then, the bottom once again went back to his timeline — back to when he and the top were just platonic childhood friends.

Landmines include but are not limited to: Sweet & naive bottom, a president story, logic is dead, slow-progressing romance, the protagonist’s name has too many character strokes, the names are hard to pronounce, too many gay characters…

- Description from novelupdates

Based on the popular Vocaloid series, by HoneyWorks, called “Kokuhoku Yokou Renshuu (Confession Rehearsal)“:

Natsuki, a third-year at Sakuragaoka High School, who holds unrequited feelings for her childhood friend, Yuu, who’s in the Film Club. However, instead of being honest about her feelings, she makes him be her confession “rehearsal” partner. Unable to say her true feelings, things start to get complicated when Miou and Akari, who are also in the Art Club, get involved! Will she ever be able to confess for real!?

While the blue light blossoms, the insignificant struggle at the bottom. He grasps the opportunity to change his fate and embarks on an unprecedented path…

The strongest King of Soldiers returns to the city of flowers, becoming his fiancée's cohabiting bodyguard!