[Whisp (Oza)] Idol no Seiyoku Kaishou Vibe ni Erabareta Boku | I Was Chosen to Be an Idol’s Living Vibrator to Sate Her Lust [English] [OCD Translations]
It seems to me she's as much a masochist as she's a sadist haha
But, well, fan-kun got laid and some intimate time with his favorite Idol, and even some commitment for more action in the future. It truly is an absolute win.
These stories usually end with the guy never actually fucking, and either getting fucked himself in the ass or just getting downright sissyfied, not to mention that whole new blacked trend going around that’s basically everything wrong with NTR, so honestly this is a fantastic change of pace, not to mention the best possible ending for a masochist like MC.