Osananajimi dakedo Seiteki ni Suki desu.

Souta and Mitsuki, childhood friends who've gotten along well since kindergarten, are now in their adolescent years. One day, Mitsuki comes to complain to Souta after hearing their classmate boast about losing his virginity. Reasoning that there's nobody else he can ask, Mitsuki suggests practice-kissing with Souta! Souta acts indifferently but internally yells an eager response. Why? Well, because he's been keeping his role as Mitsuki's best-friend, while secretly having feelings for him all this time. Sharing a clumsy kiss with Mitsuki, who's unaware of those feelings, Souta thinks it's his chance and takes on a gamble to fulfill his desire!!

(Source: Takeshobo, translated)