it a derogatory to example what an ass or bitch your being like a guy who miss the chick's mouth when he was cuming and let her past out with the cum still on her upper lip.
Art: You were such a damn upper lip cum stain, for not waiting for me
Joni: Sorry, I tired to text you but your phone is being an upper lip cum stain again
Bro, I'd like you to cum on my hat right now but it would leave a mark, and that would negate the pleasure I'd derive. I suppose we're in a Zero Cum Stain