Unsweet: Netorare Ochita Onna-tachi

I really liked this one. Like many NTR, the cuck (in this case Jun) actually gets a decent crack at the "heroine", his MILF teacher Katsuko. In fact, he even deflowers her (she appears to be almost 30 and very hot, but still a virgin apparently). The sex must not have been that great, however, because Katsuko rebuffs Jun the next day when he tries to eat her pussy. The "villain" Kazuya, sees this going down and uses it as a lever to blackmail Katsuko into submission. As the days pass, clueless Jun has no idea what is happening whenKatsuko fails to both show up for her teaching job and answer his repeated calls. While this may sound dark, unlike many here, I respect what Kazuya is doing. Though he starts out blackmailing Katsuko, he eventually wins her over with a mixture of psychology, nerve and sexual skill. But, beyond that, he seems to have real feelings for the MILF and even offers to marry her. It seemed like his offer was really genuine. Meanwhile, Katsuko falls harder and harder for Kazuya (or rather his cock), all the while claiming to hate what she is doing & professing her love for Jun. In the end, she cannot resist Kazuya's skill and becomes his sex toy, letting him cum repeatedly in her pussy. The ending is very awkward as Jun finally finds out what's going down, but probably can't do a damn thing about it.