CFNM stands for "clothed female nude male." In free sex videos and porn, this term refers to a guy in his underwear fucking a girl in his clothes. Most videos depict bulky stripper boys doing some naughty things to a naive chick. Many of the ladies in these videos are amateur ladies who get a bare-chested cocks from the big guys in the stripper's costumes. It's a way of life for the naked guy, who feels unprotected, humiliated, and under-dominated by the women in clothing.