Originated by the infamous underground rappers Tay T & Mar J in a collaboration with Drizzy, LIP is used commonly in chatrooms, on social networking websites, and through text. It is a subtle way to express the embarrassment that occurs after encountering something so funny that it is impossible to stifle your laughter whilst in public.
Can also be used to describe laughing at a computer screen, even and especially if you're all alone.
Often used repeatedly.
T: She looks like a burrito
M: LIP LIP
Generally when someone speaks to someone significantly older then them with a level of disrespect, contempt and/or in a considending tone that shows they have no respect for their elder(s).
No one likes it when someone gives them lip.
To give someone lip is practially begging them to take you over their knee and give you a spanking.
Kid: *talks back*
Adult: Don't you give me lip boy!