Chuffed to the muff
To be extremely pleased with oneself
Larissa's achievements were so amazing, she is entitled to be chuffed to the muff.
Chuffed to the Muff
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 you’re “chuffed to the muff,” aka very pleased with yourself.