Vedas suggests liquids like urine and semen to be sacred. There are many kind of Sacrifices in Vedas for different purposes. One of the sacrifices mentioned in Rig Veda is about using Horse’s semen as Soma Ras. Not to confuse this Soma as the moon god. Soma Ras appears in Vedas as an elixir. Which was the most favourite drink of god, more like their energy drink. However Soma Ras has now become extinct. It is said that it was made from some herbs. But Horse’s semen is used as Soma Ras as mentioned in Rig Veda,
Rig Veda 1.164.35…The Stallion’s seed prolific is the Soma; this Brahman highest heaven where Speech abideth.
Above is Swami Karpatri’s Hindi translation below one is by Shri Ram Sharma,
The Sanskrit words mentioned here are Ashvasya (Ashva) which means horse and Reto which means semen. In this sacrifice the semen of the horse was used as the Soma juice. Krishna Yajur Veda and Shatpatha Brahmana also mentions about Soma being semen but they doesn’t hint that it has allegorical meaning.
Satapatha Brahmana 220.127.116.11 Having thrown the (earth of the) foot-print (into the pan), he (the Adhvaryu) washes his hands. Now as to why he washes his hands;–clarified butter being a thunderbolt, and the Soma being seed, he washes his hands lest he should injure the seed, Soma, with the thunderbolt, the ghee
Krishna Yajur Veda 7.4.18.F …They call Soma the seed of the strong horse. (They call) the Brahman the highest realm of speech.
Soma Ras as semen also appears in the Puranas,
Srimad Bhagavatam 3.13.38 ”O Lord, Your semen is the sacrifice called soma-yajna…” Tr. Swami Prabhupada
Brahma Purana 7.1-3 ”O Brahmins, the father of Soma, the saintly lord of Atri was the mind-born son of Brahma who was desirious of creating subjects. Formerly, Atri performed a great penance for three thousand divine years. So we have heard. His semen attaining the state of Soma juice rose up.” Tr. J.L. Shastri
Hinduism also consider the urine of Rudra as potent remedy,
Atharva Veda 6.44.3 Thou art the urine of Rudra, the navel of amrita (ambrosia). Thy name, forsooth, is vishânakâ, (thou art) arisen from the foundation of the Fathers, a remover of diseases produced by the winds (of the body).
The Sanskrit words used here are ”Rudrasya Mutramasyamritasya naabhi” the word Mutr has only one meaning and that is Urine. Here the urine of Rudra is considered the Amrit (elixir), Rudra’s urine is not available today so this verse is of no use which is contrary to the belief of Vedic followers so this verse implies that Vedic followers should drink their own urine.