Mike was careful not to win too much in any one casino, keeping to limits Jill set for him.  After he had milked each one for a few thousand he carefully put it all back, never letting himself be the big-money player at any game, whether winning or losing.  Then he took a job as a croupier, studying people, trying to grok why they gambled.  He grokked unclearly a drive in many of the gamblers that seemed to be intensely sexual in nature - but he seemed to grok wrongness in this.  He kept the job quite a while, letting always the little ball roll without interference.