A timmy todger is when a young male wakes up with morning glory (erection as you wake up) and decides to wank (masterbate) it off, usually before school starts.
The sexual act of dipping ones erect penis into cake batter before inserting it into the partner's mouth for a blow job. Not to be confused with the Royal Tewksbury Todger, which is the same but with blueberry sauce added on top of the cake batter.