That's Bizarre: A teenager could be registered as a sex offender - after trying to get intimate with a mannequin.The 18-year-old was caught with his trousers and underwear around his ankles, rolling on the floor with the dummy from a display at an arts centre.Security guards who caught the youngster in the act admitted they had often found the mannequin with its clothes off.Police spokesman Loren McManus said: "There was inappropriate activity between him and the mannequin."That's the only way I know how to put it."The boy has been charged with indecent exposure.