ANNA Nicole Smith showed up at Hamburger Mary’s in West Hollywood to play bingo for charity last week and took home quite a prize — a barmaid. Tracy, a pretty blonde, allowed herself to be picked up by the former Playmate and was later bragging about the night she spent with Smith, sharing pictures from her digital camera with patrons at the bar. “She wasn’t keeping it a secret,” a PAGE SIX source relates. “Anna Nicole put her in handcuffs and her neck was covered with hickeys.” The source added, “Anna Nicole was doing that butt-slapping thing — it was just bizarre. And her son was in the house.” Calls to Tracy and Smith were not returned.