I Read it on wattpad. It's a BDSM Transmigration, The first world is... He body's sister is the ML's gf, ML would bully him before and started to actually like him then ML kidnapped him and they got together. Idk if this is the second arc but the ML is the emperor and the body is a enuch I think. Most important details: The ML gift Protagonist a choker I think. The first world, ML's parents are also in a BDSM relationship. ML likes to call protagonist Wife I think or some kind of pet name in the first world.
I found what you where looking for just searched a bl wattpad reading list To forever love him by theanimeoutcast Spoiler: Link https://www.wattpad.com/story/156100739-to-forever-love-him-unrevised-edition Spoiler: Authors description (This is the unrevised, in dire need of editing, cringe edition of To Forever Love Him. This book is recommended for 18 and up, and is a LGBT story.) Sun Hui is an average sixteen year old nerd boy with a loving family and great friends. One day, he is transported to Xinghai Space and is forced to play the roles of cannon fodders that all meet terrible ends. He can handle acting out tasks, but he absolutely hates being used and dying several times. After several lifetimes, his AI suddenly stops working and the Lord God is nowhere to be found. Still stuck in Xinghai Space, but with freewill this time, he decides to put his lifetimes to use. He vows to help others out and to bring justice to those who deserve it instead of being a bystander to make up for all of his tragic ends. This is his vengeance. Until then, he can only hope to get back home. Disclaimers/Warnings: •This book is based off of Quickly wear the Face Of the Devil, another system story. I do not own that book or translation. I'm only using some elements as it is in the same universe, but the characters and storyline are generally original. •This is my first BL (and bdsm) story EVER, so I apologize if it's unrealistic/crap. I'm just doing this for fun. I am not the best with mature scenes yet so they may be poorly written. Also, my wording isn't the best. •I am not Chinese so some things culturally may be incorrect •This book may trigger you at some parts. ONLY the first arc will contain rape and bullying towards the MC by the ML-if you don't like that, don't read it- but I guarantee a happy ending. Read warning in the beginning to know more. •Arc 1 is currently being completely rewritten and can be found in the revised edition published under my account here. I recommend you read that. The original arc will also be somewhat edited for those who liked the original and those who don't. •I also don't own any of the photos used, all are from google or pinterest. •Weekly updates