Gokujou Kishi Danchou no Dekiai Choukyou - Sono Kyodai Sugiru Ai, Subete Ukeirete Misemasu!

Knight commander Adam and flower‑shop girl Merle are seen around town as a perfectly proper, ideal couple, but behind closed doors their nights are extremely intense. Merle is constantly pushed to the edge by Adam’s “supreme” skills in bed, until one night she wakes up to find him staring at her and masturbating even after they have just had sex. Shocked, she worries that she cannot satisfy him and, as his lover, suggests “sex training” so she can take all of his huge love and pleasure. Adam, deeply in love and slightly off in how serious he is, responds with Spartan but overwhelmingly sweet “training,” trying to cherish her while also holding back his own desire.

Original Manga