I found this, my emphasis on the last part:

Marketing by stealth isn't the only tactic employed in relation to Tim Tams. They have also been associated with the double entendre, such as "Ten reasons why a Tim Tam is better than a man", and "Two and a half inches has never been so satisfying". These people are well aware the major devourers of Tim Tams are women. Perhaps the name "Double Trouble" is not so far off the mark. Arnott's has also reported that most Tim Tams are eaten in the privacy of the home, and forty percent of customers admit to hiding their purchase of Tim Tams from friends and family.