*NOTE: MATURE CONTENT
The story of Enkidu and Shamhat from The Epic of Gilgamesh comes to mind. Enkidu is considered a "wild man" in the sense that he lived alongside animals following his birth until the temple prostitute Shamhat was sent to "civilize" him through the act of love-making, after which Enkidu joins civilization and becomes best friends with Gilgamesh.
The part of the narrative that might interest you most is the specification of how many days in a row Enkidu and Shamhat engaged in sex.
The following is a passage from Tablet I of the Kovacs translation that describes the event.
Then Shamhat saw him--a primitive, /
a savage fellow from the depths of the wilderness! /
"That is he, Shamhat! Release your clenched arms, /
expose your sex so he can take in your voluptuousness. /
Do not be restrained--take his energy! /
When he sees you he will draw near to you. /
Spread out your robe so he can lie upon you, /
and perform for this primitive the task of womankind! /
His animals, who grew up in his wilderness, will become alien to him, /
and his lust will groan over you." /
Shamhat unclutched her bosom, exposed her sex, and he took in her voluptuousness. /
She was not restrained, but took his energy. /
She spread out her robe and he lay upon her, /
she performed for the primitive the task of womankind. /
His lust groaned over her; /
for six days and seven nights Enkidu stayed aroused, /
and had intercourse with the harlot /
until he was sated with her charms.
Translated by Maureen Gallery Kovacs
Electronic Edition by Wolf Carnahan, I998