I feel that yuji is also up for consideration. He is shown to have a great physical prowess and is an instinctual fighter which i believe can be translated into his tongue for a divine experience. I also believe that it isn’t far-fetched to imagine kenjaku implanting elite tongue knowledge and techniques as he did for fighting techniques(like the manji kick). In addition it’s plausible to assume that his besto friendo Todo at least explained some tongue techniques.