Maul was content to keep scratching behind Luke's puppy ears until he found his hand pushed away. This was just too much fun and he decided to continue this as long as possible.

He paused for a moment, hand still hovering by Luke's head. He had seen that wagging tail and knew Luke must have been enjoying what he was doing. "Oh? Are you so certain you want me to stop?" Maul said, mercilessly teasing the Jedi. "Because you don't sound like you really want me to."