A man goes to his GP because he is very constipated. His Doctor gives him some pessaries and tells him "Go home and put these in your back passage, then come and see me next week."
The man goes home and then realises that he doesn't have a back passage - but he has a front porch - so he puts them in his front porch!
A week later the man returns to the Doctors. "How did it go?" Asked the GP. " Absolutely useless" came the reply "for all the good they did, I might as well have stuck them up my A***".