Inappropriate laughter

D is here every Wednesday afternoon and "does" for the  lazies ladies of the house.
She and I share a puerile sense of humour.           
We have  literally been falling about laughing this afternoon.   It started with a picture of D's cat and his incredibly luminous eyes (see extra - rubbish shot) followed quickly by an unfortunate slip of the tongue by Ed when she answered the phone and we have gone seriously  down hill from there.         
My sides are hurting.