The act of barely inserting an unprotected penis inside a vagina in the heat of the moment, then quickly removing saidpenis to put on a condom before continuing with sexual intercourse.
Origin (A dip in the lip is a phrase used by Alabama teens who don't dip but make jokes about dipping) basically calling someone your best friend that you can't live without as in rednecks who can't live without their dip in their lip