A scaj is a scabbed over anus and surrounding area.
It is obtained primarily from rubbing one's anus on the sidewalk, but can also be obtained in other ways such as a rough night or a dirty game of hide-and-seek.
When one refers to theirself, a scaj is a synonym for butthole.
"Tim just stuck a beer bottle up his ass, now he's totally going to get a scaj."
"Mom they checked everywhere, they even looked in my scaj!"
A scabby anus (ie. An anus and/or surrounding area that has been scabbed over.) It is most commonly recieved from being rubbed on the sidewalk, though a scaj can also be obtained from an STD or a rough night.
When used in referance to one's self, a scaj is just a synonym for butthole.
"Timmie just stuck a beer bottle up his butt, he's totally going to get a scaj."
"...Mom, they felt me up, they tried to look in my scaj."