Sinopsis

The four daughters of the Onami household—Sora, Akane, Kohaku, and Sumi—have set some "rules" for their brother to follow when hugging them. He must make sure that each hug is: at least 10 seconds long; accompanied with a sniff; and, most importantly, done with lots of affection. Of course, these stipulations apply not only to mere hugging, but also to even more intimate acts. [Written by MAL Rewrite]