Hi there I cant remember this h-manga, can you please help me:
Its about a sister finding out that her little sister is being gangbang and she likes it, and the older sister finally joins them, and finally they take a photo with both of them doing the peace sign!
Thanks in advance.

Only bump after a week

A just ruler amongst tyrants

dude you got to break it down further, that's the plot of at least 50 different titles.

Starter of Controversy.

The big sister finds out something wierd about her little sister, and the big sister is in a room (probably a locker room) at school (dont remember what she was doing) this guy comes and takes her outside, and tells her to watch something, and through the window she observes her little sister with two or three guys, and the little sister is saying that the big sister nearly found out or something. And then the big sister wants to "help" her or something and in the room both get fucked, and then they smile and pose with a peace sign to the photo made by a mobile phone. And the last scene is both sisters walking away together (I think its over a bridge, not sure)

(I think the cover is both of the sisters with a mobile phone or something I cant really remember)

Thank you in advance!

I alredy found out which one it is, so thank you all for your effort >_<