The Name of that Flame is Sexual Preference

The story is set in the near future, where the "NTR" genre has been banned due to the risk of causing brain damage. Akira Inui, an unsuccessful erotic manga artist, happens to encounter NTR and is drawn to its charm... This is the story of the protagonist's passion as he pursues the "ultimate NTR" together with Harumi, a cyborg equipped with a "sexual desire reactor" that converts sexual desire into energy.

(Source: Natalie, translated)