A “crip line” is a Chicago term for a lay-up line in basketball. The name suggests that a lay-up is so easy, even a crippled person could do it, hence the name “crip line”.

This ties into the next line: “I’m slamming, jamming on the one.” Slamming and jamming are (obviously) also basketball terms; Com has gone from lay-ups to slam dunks. Doing it on the “one” suggests the “1,2” of a mic check—but Common may also be indicating that he plays the point guard position in basketball, also known as the “1”.

https://www.youtube.com/watch?v=S8H8EWvmfL4

Chicago was home to many of America’s most violent gangs, including the infamous Black P Stone Nation, the Vice Lords, the Gangster Disciples, and the Latin Kings. And during Prohibition, Chicago became notorious as the home of gangsters like Al Capone—the “original gangbangers” profiled in movies like The Untouchables. No one in Chicago is “shy” to commit acts of violence, and of course “shy” is a homonym for “Chi”, a common abbreviation for Chicago.

Common drops this line in matter of factly at the very end of a song that has mostly been devoted to innocent memories of childhood: BMX bikes, neighborhood parties, and lazy summer days. But touches of sadness and violence can be seen on the margins—fights, robberies, and here ubiquitous gang tensions. As a young man growing up on the South Side, Common had a mostly normal childhood, but was always aware of the violence and danger lurking in the background.