The word 'curb' is not necessarily interchangeable with other terms associated with 'giving head'. Curb is a step up, per say, from your typical felatio session (a couple dips deep down the throat, lots of tip sucking, some ball fondling and shaft stroking).
Curb is, more or less, a form of art.
Giving/receiving curb entails 6 or more of the following :
a BBC (big black cock, or any given african male worthy of receiving such an act);
deep throating for extended periods of time to the point of tears, the ripping of the epiglottis, and/or suffocation;
regurgitation of any previously consumed meal;
complete numbness of the lips (preferably DSLs), tongue, and jaw muscles;
wet, slippery suction-release sounds;
finger in asshole;
licking of the taint;
entire ballsack in mouth, with light suckling/tug;
eye fucking during the act;
using tongue more often than a frog does catching its prey;
and animalistic vocalization of sexual pleasure by the GIVER.
completely necessary in any act of felatio, especially curb: copious amounts of saliva, and a minimum qualifying cock size of 7.5 inches long (while hard) by 1.5 inches wide.
'give me that becky'...
Yea man, she got fucked by the Crimson chin alright!