short for cock bloker. Someone that gets between your cock and a lady you want to give it to. Thus preventing your cock from reaching its intended target.
That Camilo, man, kept groping the girls at the party and ended up cock blocking us all. What a C.B.
Dude 1: Dude this girl sucked on my C&B last night!
Dude 2: Dude ur what????
Dude 1: My fucking COCK and BALLS!!!
Dude 2: Dude thats fucking sweeeet!
Dude 1: I Know! It was tight.