The legend tells that one day Aphrodite (mother of Cupido) complained to the goddess Themis that the little Eros (Cupido) doesn't grow, so the wise Themis replied that Cupido would never grow until he had the love of a brother. Aphrodite joined with Ares and begat Anteros and from that moment the two brothers grew up together, but each time Anteros turned away from Cupido, the latter returned into a child. This charming myth teaches that love (Eros) in order to grow needs to be accompanied (Anteros).
The two angels experience pain when they are far and relief when they are together, the mirror image of the lover's feelings…
That’s why Cupido Drink ® is made by Black Angel and White Angel and they are sold together always!
…So he calls for the mischievous Puck to help him apply the magical juice of Cupido made from a flower called "love-in-idleness", which when applied to a person's eyelids while sleeping makes the victim fall in love with the first living thing seen upon awakening.
From: A Midsummer Night's Dream
by William Shakespeare.