About dummy-head mic/binaural(?) audio...

Yeah Rejet is notorious for their dummyhead mics throughout their games/drama CDs(highly recommend Alice=Alice, is it vore is it ecchi only one way to find out). Very fanservice-y, the voice acting is so top tier >u< I also recommend Dear Vocalist if you're looking for an ongoing-ish drama CD series about hot not so mentally well cute band boyfriends.
Honeybee games tend to use binaural audio a bit(like Ayakashi Gohan and Blackish House) when the characters move around on screen. I think it's pretty engaging, as if you're watching the scene unfold in live 4k HD lol. Meikoi also does that but more on the fanservice-y scenes iirc(though much more tame than anything Rejet produced).

I second Alice=Alice recommendation /.o./ my translation tool can't pick up audio only and it wasn't in text so I had to stop playing and get serious in my Japanese studies ^^; very lovely LIs teasing voices (all the tickles/goosebumps ♡)

If you prefer historical stories, I recommend Shinsengumi Wasurenagusa, especially Harada's volume. I really love this character and his story in every series, and his Hiyokuroku season is my top favourite. The dynamic between the protagonist and Harada in this season is seriously so wholesome and adorable that always make me melt so bad

I think *Love and Deepspace* uses a dummy head microphone as well. I also think it has a good amount of dialogue.
As for situation CDs,I recommend all of Rejet's series. *LOVE DON!! QUIXOTE* has a lighthearted vibe and is a choice.
Also, although they're older titles, I really liked the CDs in the *IchaGoro* series. Especially *noon!*
If you have a favorite voice actor, why not give their situation CDs a listen?
For those who don't care about the story, ear-cleaning sounds and ASMR tracks are perfect for casually experiencing binaural sound.

Haha, I'm also familiar with them because of Rejet (and Ayakashi Gohan)! I think it's pretty fun, but sometimes it does feels a bit awkward it got me a bit jumpy in DiaLovers and Alice=Alice

I like the way it can help the immersion as well! Like getting to hear where a character is coming from, or getting surprised with the MC when you hear them close lol

This is an R18 title, but *Sachi no Tenbin* also used a dummy head microphone exclusively for the H scenes.
The sound quality was poor in those parts, which was a bit of a letdown.
Similarly, *Ao no Shigyaku Midori no Higyaku* is also an R18 title that used a dummy head microphone, but it feels more like a sound novel or a situation CD than a typical otome game.
As for CDs, lately I've been playing "WITH YOU Majiriau Jikan" on repeat while I sleep. It gives me chills, and I really love it.

I've seen this on a few novels and been curious. I know that ASMR audio is getting really popular on sites like DLSite, so it seems like a natural step to include it in novels.

Is this the kind of thing that will "just work" with headphones or is there more to it?

I love it!! I love drama cds for how immersive they are, combined with visual novel, the experience just gets even more immersive!!

I haven't played many, if any VNs that have this, but boy, would I love to! (⁠人⁠ ⁠•͈⁠ᴗ⁠•͈⁠)

I used to have so many drama CDs favorited and followed so many tumblrs for translations just to experience the asmr before I knew what ASMR was. (⁠灬⁠º⁠‿⁠º⁠灬⁠)⁠♡

There were also boyfriend audio apps that were so fun and I used to play them before bed. (OMG had to Google, I saw one character I remembered and it was Sleepytime boyfriend!! But there were others that had different characters and scenarios I wish I could recall!)

If you like strictly Japanese audio, definitely recommend trying drama CDs but if you want to try English (or other languages sometimes) there's also people who post their own on other sites, graphic and fluffy ones too with dummy mics or audio adjusting to simulate it. (⁠ ⁠ꈍ⁠ᴗ⁠ꈍ⁠)

I don't really listen to otome game spin-off Drama CDs that much, but I browse the otome section on DLsite a lot, so I have some thoughts I can share about these kinds of audios.

Actually, what we call "binaural audio" is usually referred to as "Situation Voice" (シチュエーションボイス) or "Situation Drama" (シチュエーションドラマ) in the Japanese community. If a dummy-head mic was used for recording, it will almost always be prominently highlighted in the product description. After all, dummy-head mics are way more expensive than regular ones, so it's a major selling point (and naturally, these works tend to be priced a bit higher).

The level of immersion you get from a dummy-head mic is something regular equipment just can't match. Because of this, the core focus of these works is "self-insertion"—letting the listener step into the shoes of the heroine to interact with the male lead, fall in love, find comfort, and even engage in intimate acts (which is exactly why most of these audios are R-18). This is completely different from traditional Drama CDs. Situation voices are a "first-person experience," whereas traditional Drama CDs treat the listener more like a "bystander" or third-party observer listening to the characters' stories. The creative approach behind the two is fundamentally different.

Here are a few really good all-ages (SFW) works I'd recommend:
https://www.dlsite.com/girls/work/=/product_id/RJ01142235.html

On a side note, I've noticed some creators in DLsite's BL section experimenting with dummy-head mics for BL CDs or situation voices. To be honest, my personal listening experience with them was a bit... awkward. When listening to a BL dummy-head CD, the 3D audio makes you feel like a "third wheel" awkwardly sandwiched right between the two male leads. And for BL situation voices, you basically have to self-insert as a guy... (Of course, I'm sure there are listeners who enjoy this unique experience! I'm just sharing my personal feelings here, no offense intended at all.)