im looking for a yuri manga that i forgot the name of.
Its about 3 girls that are friends and one is straight (i think),
two get together but its only one sided love, one loves the other but the other loves the straight friend. The one girl in love knows that, that she isn't loved by the other but says that she is ok if she is used as a substitute for the girl her lover can't get /she screams her name in bed). and they want to keep the relationship a secret from the straight friend.

similar setting as in Girl x Girl x Boy if that helps.

edit
its a complete manga short, max 2 volujmes if even that. could even be oneshot.
Might have been labeled Shoujo-ai, and not yuri

edit number 2

Found it dear god yes, I found it!!!
it was the "If this Wish comes true" story in Kono Negai ga Kanau nara

I think it might be Kimi Koi Limit

thanks will read that one too. but thats not the one. thanks anyway.

in the manga iim looking for, they went to the same school.

Maybe one of these?

Orange Sweet Olive Blossoms
Strawberry Strawberry Strawberry
That's Why I Sigh
Traces of Snow

Moved to Yaoi/Yuri~

no sorry its not one of those.
thanks anyway