Kuroushiki's manga / #Master x Slave(4)

The art not really satisfied me but thanks to the story (used a lot of stuff and toys)and the sex scene I can give 3 star cause I like this kind of story... First couple (Chap. 1-2)bossxworker: use a lot toys, contain office sex,outdoor sex,hot bath sex.... Second couple (chap.3)doctorxoffice worker: a little bit drug usage, bondage and medical equipment usage too.. Third couple (chap.4)writerxeditor (I'm not sure):naked apron and a little bit bondage and blindfold, a few scene bathroom sex... Fourth couple (chap 5)Masters(twin) xservant:obviously threesome and bondage..... Fifth couple(chap. 6)studentxteacher :blackmailed,gang rape,bathroom sex.... Sixth couple (chap.7)roommate (??):food sex....