To be extremely pleased with oneself
Larissa's achievements were so amazing, she is entitled to be chuffed to the muff.
18π 2π
An extremely common colloqulism in the UK, meaning to be extactic with ones choices and actions.
Next time you nail that presentation at work or knock a minute off your mile run, tell a friend that youβre βchuffed to the muff,β aka very pleased with yourself.