IPZZ-009 - 3:7催● 立場逆転！俺の人生を台無しにした傲慢女クズ社長の下半身をリベンジ催●で言いなり肉便器にしてやった！ 明里つむぎ

It's not a series, and searching for '3:7' only brings up this title. The effects are a bit convenient, but since it's a 'love potion' setting, I think it's fine (though it's a turn-off when they roll their eyes back too much). That said, it requires good acting skills. As others have mentioned, the tuning fork was unnecessary.

It was fine up until the point where he used a convenient gadget—like something pulled out of Doraemon's pocket—to toy with the arrogant female CEO, but once the man swapped bodies and started ravaging her, it dragged on and I got bored. The 'ping' sound of the tuning fork was quite loud and unpleasant when listening through earphones.

The actress is truly beautiful. However, perhaps because of the difficult role where she's just being manipulated, it felt a bit unrealistic and I couldn't really get into the story.

*As the title suggests, the story is a fairy tale that you don't often see in erotic manga, where a strong-willed female president is turned into a sex slave through hypnosis, but Akari's serious acting makes you hooked, and the overall result is quite captivating! Akari suits the role of a strong-willed and prideful woman, and even though she doesn't like it, she doesn't listen to what her body tells her to do and is forced to obey the demands of a man in a helpless way, and it's exciting to see her subjugated. Akari's cowgirl position with her hair tied is really beautiful and my favorite scene. However, personally, I wasn't really impressed with the final three-person scene, so I would have liked to see something a little better about the climax part, where the story falls a bit more completely. I'm disappointed in that, but overall it was a good piece!

*I didn't really feel comfortable with the setting of sexual intercourse, but I did enjoy watching her solemnly take off her clothes and have sex, even though she didn't like it verbally.