Giz is for the most part, not an affectionate cat but when she decides she wants affection, she jumps up with "that look" in her eyes and purring like a 18 wheeler and starts with the head bumps, rolling over and pulling at you.

Amy does the reach up with her claws and gives me that look of "pick me up Mommie!" and will root her head, face down on me while purring.

Samantha just JUMPS up in my lap and wait for me to start petting her and gives me a dreamy eyed look.

Chester rolls over and gives me that "I am to cute to resist so pet me" look.