A person who likes to sit around all day, eat junk food and never exercise. Fatty's poor habits have led to FJ being overweight, and therefore called Fatty Jenkins.
-(n)the art of an overweight person giving oral sex by putting the male sex organ in their fat roles and massaging it as one would do when giving a hand job.
Michael ran out of lube so Mason used the grease from the leftover KFC to give him a fatty job.