If you're looking for manga similar to Yuru Yuri Nachu Yachumi!, you might like these titles.
The daily hardships of Hikage Miyakawa, a young girl who lives with her sister Hinata. Due to Hinata's otaku impulsiveness to constantly buy merchandise, the two girls struggle everyday to have something decent to eat.
A self-proclaimed unattractive gloomy high schooler, Hiramiya Reiji, everytime he goes to visit his close friend’s house, he gets messed around by his older sister, Sakuya. Drinking his drink as she pleases, barging into the bathroom, and crawling under his blanket in the middle of the night… Thinking that perhaps he has done something to make her dislike him, he asked his close friend whether he has any idea, but he only gets a reply in a incomprehensible way, “you still haven’t noticed it, huh” On a certain day, Reiji loses in a game and has to listen to 3 of Sakuya’s wishes. Reiji goes along with it even though he has doubts, but could he gradually begin to understand Sakuya’s true feelings…? This is the story of super dense youth and a can’t-be-honest older sister until they become a lovey-dovey married couple――
Arata Kaizaki (27) quit the job he landed after graduation in only three months. His life did not go well after that. Now his parents are threatening to stop sending money, and want him to come back to the country. He has no friend or girlfriend to share his troubles with...as he hits rock bottom a strange man named Ryo Yoake appears. Yoake invites Kaizaki to join a societal rehabilitation program for NEETs called ReLife. This program uses a mysterious drug to make him look younger, and sends him back to high school for a year...