hmm tbh i haven't really found too much evil tav/durge fic similar to that one. necessary by starkraving comes to mind & scratches the same sort of itch imo: https://archiveofourown.org/works/53022892 if you're looking for dubcon specifically, one night (every night) is an anonymous short pre-canon fic with one of astarion's less pleasant marks: https://archiveofourown.org/works/54475357 on the other hand if this includes cazstar. well. 95% of cazstar is noncon so i wouldn't even know where to start but anyone else feel free to chime in!