Hatsukoi Mounting!

Upon entering high school, You freeloads in Yuzuru's home, a childhood friend he proposed to in the past. You recalls Yuzuru being an adorable crybaby and vows to protect him as his boyfriend, but instead finds out that Yuzuru has grown to be an incredibly handsome man with no trace of his former self! Taken aback from this unexpected turn of events, he then finds out that Yuzuru wants to top him...?! The battle (?) between two people who want top each other and won't let up begins!

(Source: Shueisha, translated)