Tackled to the floor

Dan can't keep his balance and falls face-down to the floor, Kelly laughs and starts slapping the back & sides of his head.

As he starts to cover up, she reaches back and gives his ass a hard smacking. She's mounted on his lower back, and as she slaps his ass, Dan pushes himself up and says "Hey!" As he does, Kelly wraps her arms around his neck again in a flimsy chokehold.

Dan tucks his chin and gives his sister's arm a light bite, she pulls it back with a squeal, and he rolls over, knocking her off his back.