Amai sokubaku, 3-pun instant no chinmoku....sorry i just know those bcos i really dislike incest buy it depends on the story plot so this manga is okay eventhough it was about a twin....it triggers me bcos i have a twin too....sorry again bcos maybe this offended you bcos you just about a recommend manga....i am really sorry (/TДT)/
Hope this will do http://www.mangago.zone/home/mangalist/183465/
Brother X Brother by Kisaragi Hirotaka
http://www.mangago.zone/read-manga/brother_x_brother/
Brother by Ougi Yuzuha
http://www.mangago.zone/read-manga/brother_ougi_yuzuha/
Toshishita no Ryuugi by Maruya Kae
http://www.mangago.zone/read-manga/toshishita_no_ryuugi/
Teikoku Kyoudai by Eiri Kaji
http://www.mangago.zone/read-manga/teikoku_kyoudai/
BLT by Uzuki Jun
http://www.mangago.zone/read-manga/blt_burning_love_twin/
Into Your Heart through the Door by Yamada Yugi
http://www.mangago.zone/read-manga/into_your_heart_through_the_door/
http://www.mangago.zone/read-manga/deichuu_no_hasu/ (completed)
http://www.mangago.zone/read-manga/katakoi_kazoku/ (completed)
http://www.mangago.zone/read-manga/camellia_minami/ ->very fucked up+very depressing (ongoing)
http://www.mangago.zone/read-manga/fushidara_na_hanatsumi_otoko/ (ongoing) http://www.mangago.zone/read-manga/5_seconds/ -> ongoing, collection of short stories, not sure anymore which ch. has twincest, I think it was ch. 3?
٩(๑❛ᴗ❛๑)۶ can someone recommend more goos yaoi-incest/sibling manga? (=・ω・=)