Saishoku Kenbi de Hazukashigariya na jk to Hatsu H made

"Misaki Kanda" and "Kousuke Hatsuoka" are childhood friends and lovers. The two of them have been dating each other for 3 years already, but they've only gone as far as kissing... Kousuke has tried many times to initiate going further but she always refuses. Misaki is interested, but she just keeps refusing because of embarrassment. He used to be smarter but ever since they started dating, Kousuke's grades have been getting worse. As a result, Misaki feels bad for making him put up with her, so she takes the first step! This is the story up to his first time having sex with his childhood friend, a bashful high school girl who's blessed with both beauty and brains. (Source: DLsite, translated)