I guess you didn't get the joke. I'll explain. Look at your avatar. You have an alien for an avatar. That's why I said you were an alien.
Then, I played on the meaning of the word "mate." Many bad science fiction stories have the idea of aliens coming to earth and mating with us -- sometimes just for kicks, sometimes to save their species or whatnot. "Mate" as in procreate (definition #1, verb).
So I was saying, you are an alien, come with orders to "mate" with us, and although you are trying to keep it secret, you leak your true purpose in your language. Ok, maybe that's not hilarious, but it's at least a little clever.
It reminds me of the old Damon Knight story, "To Serve Man." They made that one into a Twilight Zone episode. Everyone thinks the aliens are nice, here to serve us, because they are very attentive and have this book called "To Serve Man" they carry around with them. Last line of the story: "It's a cookbook."