It was a jumper.
She sat down and slid her foot through.
Mommy: "Ahp, wrong hole."
Joey: "Oh, okay." (She puts her foot through the right hole, and then she smiles at me, in a mischievous way. She then begins to put her other leg through the sleeve)
Mommy: "Ahp, wrong hole again!"
Joey: "I just checking you!" (Smiling grandly.)
Mommy: (slowly, as comprehension dawns) "Joey, do you mean you are just checking to see if I'm paying attention?"
Joey: "Yep!"
That is 100% Mark right there.