Verily Dadhyak Atharvana proclaimed this honey to the two Asvins, and a Rishi, seeing this, said (Rv. I, 117, 22): 'O Asvins, you fixed a horse's head on Atharvana Dadhyak, and he, wishing to be true (to his promise), proclaimed to you the honey, both that of Tvashtri and that which is to be your secret, O ye strong ones.'

In plain words: The Vedic poet tells how the Asvins put a horse's head on the sage Dadhyak. Wanting to keep his promise, he taught them through it the secret honey teaching.