(That website claims it's an Aussie thing, but KiwiSamurai assures me it is a New Zealand practice and custom.)
You bite off opposite corners of a Tim Tam, put one bitten-off corner in a mug of hot tea (or coffee), and suck. The moment the hot sweet tea is in your mouth, stop sucking, and eat the Tim Tam before it dissolves into a sticky mess.
(You can, briefly, see how the hot tea streaming through the biscuit has melted the chocolate in that line, before the biscuit begins to feel a bit soggy in your hand and needs eating now.)
