fuzzy seam
The area of skin between the scrotum and the anus (male) or the vaginal opening and the anus (female) having which the abundance of hair and underwear lint of which usually causes chafing resulting in a pink, sore, shiny, and fuzzy mess.
After my soccer game, I straddled the mirror on my bathroom floor and gave my fuzzy seam a once over with the three-finger swipe. -Smell THAT!