What is center back?

The anus (asshole) where some people will hide contraband or things they don't want found in their possession such as drugs.

I got strip searched at jail, but I hid my drugs in my back center pocket.

center back - video

Center Back is the 2 people in the center of the defensive line on the soccer pitch. One of the hardest and most stressful positions in soccer.

Ethan is one of the center backs on the team