I was thinking of a D&D campaign that would appeal to me and my kinky friends and this is what I have so far. Feel free to comment if you have your own ideas to add to it.
The campaign takes place in a fantasy world where BDSM is a widely accepted and even celebrated part of society. The players start as adventurers who are hired by the "Mistress of the City," a powerful dominatrix who rules over the land with an iron fist. She tasks the players with exploring and conquering various dungeons and castles that have been overrun by rogue BDSM practitioners who refuse to abide by the city's rules and regulations.
Each dungeon and castle presents unique challenges that incorporate BDSM themes and elements. For example, the first dungeon could be a "Bondage Labyrinth," where the players must navigate a maze of ropes, chains, and other restraints in order to progress. The second could be a "Sadist's Citadel," where the players must face off against a powerful sadist who has enslaved a group of innocent villagers.
As the players progress through the campaign, they discover that the rogue BDSM practitioners are actually part of a larger rebellion that seeks to overthrow the Mistress of the City and establish a more radical and anarchic BDSM culture. This leads to a final confrontation between the players and the rebellion's leader, who turns out to be an old friend of the Mistress and someone who has a personal grudge against her.
Throughout the campaign, the players can choose to embrace the BDSM culture of the world or reject it and stick to more traditional forms of adventuring. The Mistress of the City rewards those who embrace the culture with powerful magical items and favors, while those who reject it may face social ostracization or even persecution. The choice is up to the players.
D&D Ideas
I believe there was a deviantart group called "boundnd" or something to that effect, it had some resources and expanded rules for bondage mechanics. If I find it I'll link it here.