Krishna Yajur Veda 7.4.19 ((exclusive)) -

Most scholars interpret these mantras as highly symbolic acts meant to transfer the "semen" or vital energy of the stallion—representing solar power and virility—to the queen to bless the royal lineage.

The Krishna Yajur Veda is a collection of sacred hymns and verses that were revealed to the ancient Indian seers and sages. The seventh chapter of the Krishna Yajur Veda, also known as the "Muktikopanishad," is a comprehensive treatise on the nature of reality, the Self, and the ultimate reality. Verse 7.4.19, in particular, is a pivotal mantra that summarizes the essence of the Upanishadic teachings. krishna yajur veda 7.4.19

From that day, no Vedic priest would offer the samidhs singly. They always placed the Aśvattha and Nyagrodha together, reciting that verse. And they taught their students: Most scholars interpret these mantras as highly symbolic