Excretion
From Tardis Wiki, the free Doctor Who reference
Excretion was one of the seven characteristics of life. (AUDIO: A Handful of Dust)
Craig Owens suggested that the Eleventh Doctor excreted some sort of gas which made people love him. The Eleventh Doctor denied his, claiming that he never excreted "any weird alien gases" at Craig yet he loved him. (TV: Closing Time)