English Sex Friend Osananajimi Shojo to Doutei wa Hazukashii tte Minna ga Iu kara - The Animation 01 | セクフレ幼馴染～処女と童貞は恥ずかしいってみんなが言うから～ THE ANIMATION

The protagonist is eating at a restaurant when he runs into his childhood friend. After making fun of him for being a virgin, she proposes for them to lose their virginity together; which begins the path of the protagonist of becoming a sex friend with his childhood friend.