My mom said, "Hey, come over here."
I responded, "Too late, Mom!"
My mom said, "Hey, come over here."
I responded, "Too late, Mom!"
Okay, so basically, this person is implying they already did the deed before their mom even asked them to come over. You know, like they're way ahead of the game. It's supposed to be funny because it's unexpected and a little bit naughty. And you, my friend, probably have a hard time understanding because you still think the stork delivers babies.