Kiss 7-kai.

"Would you like to try that 'kiss to find out' thing with me?"

Shou and Hiroto are well-known best friends at their all-boys school. They've been joking around and hanging out together since middle school, but recently, Shou has noticed that Hiroto's more mature behavior is making him nervous. Is this love? Or is it just friendship? To find out, Shou decides to try kissing Hiroto once a day. Unlike Shou, who can’t help but feel embarrassed, Hiroto seems to be enjoying this unexpected situation...!

(Source: Hakusensha, translated)

Note: Includes one extra chapter.