Jeffrey Leg Day
A 'Jeffrey Leg Day' is a session in the gym where you tell the lads you are doing legs, but you do arms instead.
Jeff: Ah lads, I'm aching after doing legs in the gym.
Lads: Piss off mate, I saw you doing curls in the mirror & you have legs like a sparrow, you clearly did as Jeffrey leg day.
Lads: Piss off mate, I saw you doing curls in the mirror & you have legs like a sparrow, you clearly did as Jeffrey leg day.