https://www.dlsite.com/maniax/work/=/product_id/RJ01067886.html/
https://www.dmm.co.jp/dc/doujin/-/detail/=/cid=d_277434/

Base +20, stupid army +10

She betrayed her bf way too easy and fell as easy as well to the point she already was making plans with the yarichin about their next outing...

Base +18, nowittycomment +16, your_name +6

Well if I am reading it correctly she says she was trained by her ex and she was already slutty by the time the mc dates her who she says thinks she's pure. Rather then ya know, showing him you aren't as pure as he thinks but, whatever.

Base +8

Pay attention to the fade-out and the inner monologue. This is in his head, and it explains a few oddities.

1. Her sudden curled hairstyle.

2. Haruka is naive and experienced at the same time. She was tricked into going to a hotel, yet she's also a blowjob expert due to her previous love.

Base +24, your_name +6

^Description on dlsite say something about imagination, so I think you're right. Panel 3 seems to show this.
She always call him on a certain time every day, so he become paranoid when she doesn't. Then she calls him as she usually does on pg 18.

Interestingly, DMM and Dlsite desciptions for this are completely different, I wonder why.

Base +8, your_name +6