Black summoner hentai is such a funny rabbit hole. I'm not an expert on specific titles, but from what I've seen, the scenes that always stick out are the ones where the summoning power itself is the tool for intimacy. It's less about the creature summoned and more about the process. Like, a scene where the summoner's magical circle is repurposed as a binding array, using the incantation's rhythm for something else entirely.
That tactile, arcane feedback loop is the unique part—the power isn't just a prelude to a standard scene. The summoner's focus, the mana cost, the potential for loss of control if their concentration breaks mid-ritual... those constraints build a specific kind of tension you don't get elsewhere. I vaguely recall a doujin where the summoned familiar was a shapeshifting slime that acted as an extension of the summoner's will, creating scenarios that were literally impossible through normal means. The mechanics of the power dictated the entire dynamic.
It's a niche appeal, for sure. The artistic focus often shifts to depicting the magical energy as a physical, almost liquid presence, which is a visual signature you don't see in other subgenres.