Board Thread:Naruto Discussions/@comment-26508646-20150704031517/@comment-25549954-20150711214915

Some thing appearing in subconscious has to have the chakra in the first place like Kushina appearing in Naruto's subconscious (chakra transfer) or Dan in Tsunade's subconscious mind(possession or chakra transfer). After Naruto completely linked with Kurama he could enter into a deeper level of consciousness because Kurama had beasts chakra that explains his ability, it is deeper level or more easily explained Kurama's subconscious. Before Son Goku was sealed he told other Bijuu and Jinchuriki that he gave some of his chakraand they gathered here because of Yonbi's request. Obito also says that chakra is the power to connect worlds or something so I thought it is because of chakra that they can link and communicate with each other not physically but through subconscious and that is what Hagoromo meant.