Responses
You can look for more under this tag http://www.mangago.zone/tag/Threesome/ but here are some I have read
http://www.mangago.zone/read-manga/pet_keiyaku/
http://www.mangago.zone/read-manga/futari_no_musuko_ni_nerawarete_imasu/
http://www.mangago.zone/read-manga/choco_strawberry_vanilla/
http://www.mangago.zone/read-manga/uchi_wa_futago_de_teippai/
http://www.mangago.zone/read-manga/bokura_no_mitsudomoe_sensou/ (ch 2)
http://www.mangago.zone/read-manga/kuroko_no_basuke_dj_vanilla_shake/
http://www.mangago.zone/read-manga/another_soundtrack_from_our_daily_lives/
http://www.mangago.zone/read-manga/junk_boys/
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