This manga was pretty cool, i really enjoyed it ^^ (Not in sexual way(?) xD)
But i have one question. Why are some mangas pink? (Like this one for example) is it some error or marking it as adult content or something?

I know some mangas are printed on various coloured paper, and the scanlators fix them up. I've seen a few non-yuri/non-adult ones that have been like that too.

As to this story, I really like it. Clearly aimed at a different (older? lesbian?) audience than a lot of yuri is, so I have to "shift gears" a little to really enjoy it but definitely worth the effort.

Erotic asphyxiation and yuri.
It's like bread and butter come together with strawberry topping!

hmmm I almost wonder if this should have a supernatural tag? maybe, but that is open for interpretation, I hope that they find each other and get together in the future though :)

A story that is a nice change from the usual. Adult, kinky and existential.