'Bash the bishop' - This originates from when the Bishop Of Cum Hardy was battered by a gaggle of altar boys after he was caught blimping up their cassocks when they were bending over to pick up hymn books that had been lashed on the floor. They duffed him up in the vestry and stuffed loads of those wafer flying saucer things from the tabernacle in his gob.
Nowadays it relates to when you can't get a lob on when your bird is lying akimbo ready for your monthly chore, you therefore smack your donger around with a few slaps on the chest of drawers to liven it up.