In a song on his album "Rudebox" Robbie Williams sings "Never touch that even if you want to". What are you not allowed to touch?

Explanation

"Rudebox" is the seventh studio album by English singer-songwriter Robbie Williams, released on 23 October 2006 in the United Kingdom. The album features collaborations with William Orbit, Mark Ronson, Soul Mekanik and two collaborations with Pet Shop Boys: "She's Madonna" and "We're the Pet Shop Boys". Five singles was released from the album: "Rudebox", "Kiss Me", "Lovelight", "Bongo Bong and Je Ne T'Aime Plus" and "She's Madonna".