So, chapter 35-36 are what actually happened from Nagi's point of view, which we had previously gotten an incomplete account of from following Airi's perspective.
Airi put on earbuds and listened to a hypnosis recording, and proved to be very susceptible to it. By the time Nagi noticed, Airi had put herself into a trance. Nagi made a few impulsive suggestions while she was in a vulnerable state, resulting in Airi becoming rather confused on what is love and fear, partly due to how Nagi worded the command to get Airi to stop acting like Nagi, which caused her to freak out.
As a consequence of this while walking home Airi began to act quite strangely, and then become very forwardly affectionate once she started to truly feel panic over the oddities she could notice. At this point, Nagi came to fully realize just how awful the situation was, presumably from the angle of abusing the trust of the person she most cares for, and asked for a hug before putting Airi back into a trance and walking her home, apologizing the entire way even though she could not be heard.
Short version: Nagi accidentally/on purpose put her bestie, whom she's into, into a situation where she would artificially reciprocate. She didn't go through with it, but she only pulled back at her own door, with said bestie saying she 'want you to be with me' (implied offer of physical intimacy)
Exactly how reprehensible she is for mind-screwing Airi is up to the reader to decide, as well as how much intentionality went into it versus veering wildly between impulsive choices and having basically no idea what she was doing. Either way, not a great look for her.