What is Farm Hand?
1.
An open handed slap on a hot ass, occasionally followed by a hard tooshie squeeze.
The phrase has its origins in the agricultural industry, where farmers would often slap their cows hard to get their attention. This gesture is an adaptation, its primary intentions being to rouse the attention of females, and to treat them as if they were cattle.
"Damn, Jenny has a hot ass. I'm gonna give her a farm hand."
or
"Last night while I was hooking up with this girl, I have her a huge farm hand. She'll be marked for at least two weeks."