Hello! I have a couple ideas/characters to float your way. Also open to cross-canon with your obscure characters and DS if you like how potential chemistry goes.

Dark Scnheider/Yor: A legendary wizard with a mastery of multiple magics, he has also mastered Illusion and Charm magic. While I don't think he can use Illusion for multiples of himself, we can do that anyway if you'd like.

The main idea is Yor failing to assassinate him and DS using his magic to basically hypnotize/mind control her with. So while he's working on her mind (he can insert images and actions into the mind that seem real, even the pleasure--so strong he convinced a virgin that she lost her virginity to him) he can also work on her body physically. We can set it in his world of fantasy if this sounds good.

He's walking dirty talk as well, and has a canonically big dick that he refers to in a variety of different ways.

Cloud/Tifa: I love them as a pairing and don't mind build up, but I admit my idea is based in assumed CR. Them as a couple and a made up Duplication Materia that goes off.

It can be two Tifas on Cloud, or two Clouds on Tifa..or we can switch from one to the other if you like the way they interact with one another.