In the 1952 Warner Brothers Cartoon Feed the Kitty, a big brutish bulldog called Marc Anthony ends up with a small kitten as a 'pet.' The kitten likes sleeping on Marc Anthony, and as it kneads his back to get comfortable, a wonderful array of comically pained expressions pass over the dog's face.
These same expressions will pass over your face, as your child digs his sharp little nails into your chest, and repeatedly kicks you in the testicles.