A term derived from Roman religion, referring to a priestess of Vesta. The term refers to a sacred duty performed by virginal (sexually pure) women in many esoteric traditions. In Roman times, while still little girls, they were chosen from prominent Roman families. Their duties included the preparation of sacrifices and the tending of the sacred fire. If any vestal broke her vow of chastity, it is said that she was entombed alive. The vestals had great influence in the Roman state.
"The woman is the vestal of the temple; thus, the fire of the temple is lit by the vestal. In ancient times, the fire was guarded and lit by the vestals. This symbolizes that only the woman has the unique capability of lighting her husband’s fire of Kundalini, which is the fire from our body or our temple. The temple of the very high, living God is our body and the fire of this temple is the Kundalini, which our vestal-spouse lights by means of the same sexual contact, or Sexual Magic, as taught in the book The Perfect Matrimony or the Door to Enter into Initiation, and as well within this current book. In this present time, the Roman Catholic Church has totally lost this tradition. That is why we see that in this Roman Church the fire of the temple is lit by acolyte boys, an action that is not only an absurdity, but moreover, a very grave sacrilege and an insult to life itself." - Samael Aun Weor, The Revolution of Beelzebub
"In that [past] epoch, there were sacred priestesses inside the temples, special Vestals. The celibate male initiates worked with these Vestals. In this day and age such women inside of the Lumisials would not be beneficial... They would be scandalous. Therefore, in this day and age, the Maithuna, Sex Yoga, can only and must only be practiced between husband and wife, within legitimate, constituted marriages." - Samael Aun Weor, The Gnostic Magic of the Runes