http://www.mangago.zone/read-manga/uchi_wa_futago_de_teippai/
http://www.mangago.zone/read-manga/futari_no_musuko_ni_nerawarete_imasu/
http://www.mangago.zone/read-manga/ienai_itami_o_daite_iru/
http://www.mangago.zone/read-manga/mayonaka_no_oyatsu/ (with his uncle though, but really cute
thse are with brothers but not blood related
http://www.mangago.zone/read-manga/kyoudai_no_rule/
http://www.mangago.zone/read-manga/crown_craze/
http://www.mangago.zone/read-manga/koi_nanka_shitakunai/
http://www.mangago.zone/read-manga/bokura_no_negai/ (this one's cute but really slow)
maybe these could help
http://www.mangago.zone/read-manga/miruku/
http://www.mangago.zone/read-manga/stalemate/
http://www.mangago.zone/read-manga/mitsubana/
http://www.mangago.zone/read-manga/sayonara_boku_no_princess_lolita/
http://www.mangago.zone/read-manga/ao_no_exorcist_dj_twin_s_tail/
http://www.mangago.zone/read-
http://www.mangago.zone/read-manga/kyoudai_biyori/
and
http://www.mangago.zone/read-manga/haikei_niisan_sama/ <-- the purest form of incest you'll ever find ;~; (no smut)
Maybe you can find something here :)
http://www.mangago.zone/home/mangalist/97503/
http://www.mangago.zone/home/mangalist/97514/
Does anyone know yaoi manga twincest or incest? Something not too psychological or creepy please. Some beautiful smut and not too much of an age difference is pretty good too. (〜￣△￣)〜 It can be touching and sweet too.....