Priapus and Lotis

But crimson Priapus, guardian and glory of gardens,
Of them all, was captivated by Lotis:
He desires, and prays, and sighs for her alone,
He signals to her, by nodding, woos her with signs.
But the lovely are disdainful, pride waits on beauty:
She laughed at him, and scorned him with a look.
It was night, and drowsy from the wine,
They lay here and there, overcome by sleep.
Tired from play, Lotis rested on the grassy earth,
Furthest away, under the maple branches.
Her lover stood, and holding his breath, stole
Furtively and silently towards her on tiptoe. . .  Fasti I Jan. 9 A.S. Kline

In Ovid's Fasti,[19] the nymph Lotis fell into a drunken slumber at a feast, and Priapus seized this opportunity to advance upon her. With stealth he approached, and just before he could embrace her, Silenus's donkey alerted the party with "raucous braying". Lotis awoke and pushed Priapus away, but her only true escape was to be transformed into the lotus tree. To punish the donkey for spoiling his opportunity, Priapus bludgeoned it to death with his gargantuan phallus.

Priapus and Lotis

Priapus was described as the son of Aphrodite by Dionysus, or the son of Dionysus and Chione,[1] perhaps as the father or son of Hermes,[2] and the son of Zeus or Pan, depending on the source.[3] According to legend, Hera cursed him with impotence, ugliness and foul-mindedness while he was still in Aphrodite's womb, in revenge for the hero Paris having the temerity to judge Aphrodite more beautiful than Hera.[4] The other gods refused to allow him to live on Mount Olympus and threw him down to Earth, leaving him on a hillside. He was eventually found by shepherds and was brought up by them. 

Priapus joined Pan and the satyrs as a spirit of fertility and growth, though he was perennially frustrated by his impotence. In a ribald anecdote told by Ovid,[5] he attempted to rape the nymph Lotis but was thwarted by an ass, whose braying caused him to lose his erection at the critical moment and woke Lotis. He pursued the nymph until the gods took pity on her and turned her into a lotus plant. The episode gave him a lasting hatred of asses and a willingness to see them destroyed in his honour.[6]

Priapus: Wikipedia; Theoi; Parada.