Im looking for a yaoi where the uke falls in love with his sister's boyfriend or he falls in love with the boyfriend of a female friend or somethin like that.

Sorry if my english sucks, it's not my native language

Suki ni Naccha Ikenai Hito - this is the only one I know.

I remember this one manga where the boy likes his sister's boyfriend... His sister becomes tomboyish, trying to make the guy like her more. The boyfriend appears in his window or something... I don't remember the title!!! Ugh!!

Is it Beautiful Beautiful Beautiful: http://www.mangaupdates.com/series.html?id=11182

Quote from dalek

I remember this one manga where the boy likes his sister's boyfriend... His sister becomes tomboyish, trying to make the guy like her more. The boyfriend appears in his window or something... I don't remember the title!!! Ugh!!

Karada Meate de Warui ka 4th chapter I think.

I read it years ago but i'm almost sure Saigo no Shouzou fits, Yume no Kodomo. And also Ooparts Sex but with only one chapter there is not much i can say...

And Alooong the lines:

Koi ga Bokura wo Yurusu Hani , Gosan no Heart, Seven days.

** "It's so warm that, Before the snow has a chance to stick, He melts it for me." **

Thanks for the suggestions I love CJ Michalski's work so i really liked Suki ni Naccha Ikenai Hito and Beautiful Beautiful Beautiful almost made me cry i'll try the others. thanks again.