A particularly sexual person, generally strait, but can often be lesbian or threesome. A Fuck Duck often touches people in a sexual manor constantly. They are often characterized by staring at a person they are atracted to and then touching them sexually without thier permision but in a positive manor. NOT RAPISTS.
"Dude your acting like a total Fuck Duck today"
"I know i just wanna grab her ass"
and then proceding to tap her ass