I don't see any mind control, contrary to the tags. I do see an aphrodisiac spiked drink on 35 (comment that it was spiked with an aphrodisiac on 47). But that tag should be "drugs" not "mind control" The wavy circles are about the aphrodisiac working. The phone being used is just being used as a phone to call the girls.
Darker haired girl on page 2 is Miho, lighter haired girl on page 3 is Haruna. Both are old friends who also grew up childhood friends with the teacher in blue (most likely Makoto), who they called "Oniichan." He's now a teacher at their school. Miho has secretly gotten engaged with Makoto, but of course it can't come out because they're teacher and student at the same school. (The gym clothes and bloomer cosplay sex would make it even more scandalous.) The ugly guy in red is also a teacher, and he has a grudge against Makoto (envy, but also Makoto spotted him being a chikan on the train, though he managed to get away without being arrested. He then later transferred to the same school.)
Haruna invites Makoto out to a karaoke box. The ugly teacher arranged for spiked drinks to be delivered to both of them, Makoto ends up losing his wits and taking Haruna back to her room and fucking her. He then uses photos of this event to blackmail Miho on Makoto's behalf. After having sex with that guy, Miho meets up Haruna, who admits what happened, and claims that she was put it up to it by the ugly teacher, who blackmailed her over photos of him raping her. Miho doesn't fully believe her, knowing that Haruna was probably pissed at her for snagging Makoto when they both liked him.
Anyway, it escalates and by the end it's fully NTR and she gets off on the pleasure of cuckolding him.