 If you liked
Sokonashi Freefall Romance
|
 ...then you might like
Bi no Isu
|
First 3 chapters in Bi no Isu and 6 chapter of SFR involve rape by toys. Both seme act violent while uke don't fight with them (their reasons for that are completely different though). Both stories have scary and dark aura, although SFR is more graphic and give you much stronger feeling of sick relationship.