CF-ing is that act of one fucking his or her cousin. It's most abundant in white trash familys. If they have offspring they tend to have mulitple limbs or have a slow process of thought. These people are known as CF's.
Y'all my cousin says I am the best CF in the family. She says I am a pro at CF-ing!
When a guy is fucking a girl, usually the little sister of his best friend. The girl is under 18 or is not ripe in womanhood yet, she is still in puberty. It's one of the most severe cases of mackin
Man that wankster is so horny! He went from mackin on his friend's sis, to srucking her!