I'm desperate, I've been googling for days but I can't find a manga that I never finished but was planning on finishing at some point. And no it's not a hentai it's just borderline

Here is the best discrimination I have as I remember it (it's been a while)
-for one it's a bit similar to nana to kaoru

It's about a guy that works at a sex store and tests out the merchandise on himself regularly. Then one day he meats this girl that blackmails him into a weird almost bdsm relationship. Sometimes she is on a leash and sometimes he gets to take pictures of her.

I know this isn't the best description but it's all I can remember.