If you hear this often, I take it you're running some cocky/funny stuff? And even if you are, they should be telling you this stuff with a laugh and in good spirits.

Anyhow, if they're laughing about it, then stick with it and don't shift gears. Dictate your shit to them as if were your little sister:

"Well, maybe if you behave yourself like a good little girl, I'll give you a special treat."

blahblahblah

"What? what was that? Oh, you naughty girl . . . Why I ought to spank you."

blahblahblah

"I've developed this system. I like to call it, The carrot . . . . and the stick."

blahblahblah

"A good girl might get a kiss on the cheek wheras a bad girl . . . " (wave your finger back and forth and shake your head back and forth) "She gets a spanking" (But you motion your hands as if you'd 'massage' her ass.)

Absolute poker face necessary.