Someone getting fucked with the stump. And yes thematically it would be a nice fit. Zhu's hand-ectomy leads to the big triumphant moment in canon where she goes, actually fuck destiny, I can achieve great things no matter what body I have. Plus the fisting is already canon. Also sometimes she uses magic to attach a hand made of glowing light to her stump, and imo it would be a cute scene for her to fuck her wife with the magic hand.