Answer

Some of the images ‘let the cat out of the caper’ which means let the cat out of the bag (told the truth), a caper being an adventure that Batman and Robin (his sidekick) got up to. His father’s capers included having an affair and using company expenses to pay for his evenings out with this woman (lines 10/11)

Other lines include the headline- styled line 12 ‘Holy robin-redbreast-nest-egg-shocker!’ the phrase holy Robin would be used in the cartoon to express surprise when addressing his sidekick Robin. It is the shock of his father having an affair and how shocking it is.