From Rap Dictionary
- Marijuana is sometimes sold as little blocks. So, breaking off some means to share the good stuff with others. "Break ya off something" -- Cypress Hill (Insane in the brain ).
- To bring some one to cum. "Goin' to break you off, yeah babe" -- The Roots (Phrenology [2002?])
- breaking one off also means punching someone "broke him off somethin fierce"