on milking other animals

who came up with the idea? i mean, who was the first person to actually *squeeze* an animal's teats, and what the hell was going through his mind??

an even bigger question is: how the hell did he manage to explain himself to whoever he taught?
"yeah, i was standing next to the goat minding my own business when i fell suddenly, and the only things i could grab onto were her wobbly bits... next thing you know, this stream of milk's hitting me in the face!"

or the first reaction:
"you want me to pull on what??"
...
"so you're telling me you want me to feel up that goat??"
...
"and you drank it?!"