'Of course I won't laugh, said the doctor. I'm a professional. In over twenty years I've never laughed at a patient.'
'Okay then, said the embarrassed patient who proceeded to drop his trousers, revealing the tiniest 'man thingy' the doctor had ever seen. It couldn't have been bigger than an AAA battery.
Unable to control himself, the doctor was visibly trying to stifle a titter, before bursting out laughing.
After a couple of minutes he managed to regain his composure. 'I am so sorry,' he said. 'I don't know what came over me. it was most unprofessional of me and I promise it won't happen again. Now, please tell me, what seems to be the problem?'
...'It's swollen,' he replied.