Board Thread:Theories and Speculation/@comment-25139119-20150807165411/@comment-6769189-20150811180251

The Tailed Beasts said multiple time that the place they spoke to Naruto is based in the Tailed Beasts mind and that perfectly synced Jin can enter there.

Naruto was making physical contact in the real world, that's then they made the transfer. The agreement to do so happened in the Tailed Beast Telepathy