Not sure if this is the right sub for this, but I've been looking for a doujin for a long time but can't seem to remember it's name. The doujin had 3-4 (though I'm leaning more towards 3) chapters. It had 4 characters: Fsub, Fswitch, Fdom and Mdom. In the first chapter, the Fsub (curvy chick) meets Fswitch (petite futanari) and submits to her. I don't remember the details but they end up separating and the Fswitch meets the Fdom on a rainy night and the Fdom takes her under and makes her submit to her and wear a cage. The second chapter follows the Fswitch's training at the hands of the Fdom as she breaks her while the Fsub meets Mdom and starts submitting to him. Later, Fdom and Mdom meet and decide to have a session together with their 2 subs. Fswitch is surprised to see Fsub. In chapter 3, Fsub and Fswitch are seen talking on a bench, while the 2 doms secretly listen in on their conversation. Fswitch admits that she likes being a sub more. Don't remember what happens next.