
Ooof, really disliking the FL after skimming through the raws.

I'll elaborate a bit, so spoilers for Ch 15-16:
One of the girls the ML is helping slips as they're leaving the koban and he catches her. She forces a kiss on him which the FL sees; she runs away, ML tries to explain, but FL leaves in tears. She gets home and laments over the new underwear she wore for the ML, and thinking she's a fool, etc. The male teacher rings her about something she forgot at school, and she's all like, "I'll get it now". He's confused though, since he thought she'd be out on a date and she's all like "Well..." So he knows something's up and asks if he can come over her house.
Anyway, he visits her and sees she's been crying and guesses that it's something to do with the ML. He hugs her, she hugs him back. Right on cue, ML appears. He starts going off on Kaoru about how he's not just a regular colleague-- he brings up the time Kaoru kissed the FL and accuses him of deliberately using feminine speech to lower the FL's guard to take advantage of her. FL slaps the ML and gets angry that he's talking badly of her friend; she asks him to leave.
Kaoru and FL are inside her apartment, she's trying to calm down and apologises for involving him. He comes on to her, kissing her hair, and asking her if she can't think of him instead; that she'd be happier with him and he won't make her cry. He tells her he's never really been interested or reacted to other women, but he does with her. He unzips her top and presses his erection against her. Btw, she's wearing the sexy underwear she planned to show the ML-- a frilly open nipple bra with ribbons. Kaoru undoes the ribbon so her nipple is exposed. FL cover up her boobs with her jersey, but he sucks/licks her nipples over it. She reacts and gets visibly wet. He tells her to just become his and unzips her top again. He starts to pull down her pants, but stops when she calls his name and sees her crying. He covers her up again and apologises for causing her tears. He gives her a gift, kisses her on the cheek, and asks her to seriously consider him before leaving.
She then has a sexy dream about the ML. After some lewd stuff with the ML, he starts using a vibrator on her. Halfway through it though, her dream shifts from the ML to Kaoru and he makes her come as she wakes up. She remembers her troubles with the ML and what happened between her and Kaoru and is overwhelmed by all that's happened.
The next bit's something to do with a magazine and FL is asked to model alongside Kaoru (who is revealed to be a former model). Some more stuff happens: FL gets hit on but Kaoru jumps in, the FL wears the wrong outfit (a skimpy devil bikini), they're asked to pose extremely close during the shoot.

I actually really like their dynamics! They've made it work for them, which is always nice to see.
My favourite 3P is still Boys Love! by Matsumoto Miecohouse though ( https://futekiya.com/boys-love/) Equal love all around lmao (though, fair warning to anyone who does read it, it gets real dark and heavy)

Renta link- please support the author if you're able!
https://www.ebookrenta.com/renta/sc/frm/item/142194/
Oh god, he's a cuck lmao