recommendation

http://www.mangago.zone/read-manga/ibitsu_no_kakera/ (though it's pretty messed up)
you can also try looking through this list:
https://www.mangaupdates.com/series.html?category=Incest%2509_Older%2BUke%2BYounger%2BSeme%2509&genre=Yaoi&exclude_genre=Doujinshi&perpage=50

http://www.mangago.zone/read-manga/suutsu_wo_kita_akuma/ part 1 = chapter 5
http://www.mangago.zone/read-manga/ouji_to_joujin/ part 2
http://www.mangago.zone/read-manga/himegoto_wa_ouji_no_tashinami/ part 3

brothers without blood relations:
http://www.mangago.zone/read-manga/brother_ougi_yuzuha/

http://www.mangago.zone/tag/incest/

heart ni goyoujin ch. 2, abarenbou kareshi ch. 3-3.5, Anohito to Nitenai Kuchibiri ch. 3+5, Kizudarake no Airabuyuu ch. 3

http://www.mangago.zone/read-manga/doko_ga_ikenai/
http://www.mangago.zone/read-manga/juukei_hanazono/tr/119139/page/88/
http://www.mangago.zone/read-manga/sawatte_tokashite/an/sawatte-tokashite-chapter-8.html/2/

brothers without blood relations:
http://www.mangago.zone/read-manga/familiar/
http://www.mangago.zone/read-manga/zankokuna_kimi_to_tomoni/
http://www.mangago.zone/read-manga/melancholic_trickster/
http://www.mangago.zone/read-manga/otouto_ja_irarenai/ ongoing

Omg you have to read not equal that manga is amaZing

http://www.mangago.zone/read-manga/hinyari_rouka_mangekyou/ (ch.: 5-6.)

Thanks everyone !! :D