A particularly poetic way of telling someone to give you a blowjob. The "liplock" in this case refers to the manner in which the recipient of this term will wrap their lips around your "fuck stick", which is a fancy term for your penis.
The recipient of this term will be so impressed by your verbal prowess that they will not be offended. This allows you and your friends to snigger openly at this person's stupidity without fear of rebuttal.