When you have a long day and you cant quit itching your crotch.
Or when you are chapped between the balls and your legs/ass.
Simply put: Itchy crotch.
When you are critchin' and your only wish is that lotion would fall from the sky.
After a long day of swimming in the ocean it hurts far too bad to walk to your house or hotel. "Man do we have to go to the house? I'm critchin' really bad."
When everybody is wathcing you and you are wiggling to scratch the itch in your nuts. "Dude, make a distraction. I'm critchin'."
When picking your ass just doesn't do the job. "I'm not pickin my ass man, I'm hardcore critchin'."