Challenge yourself, said the Professor. He was a short man with fierce, beady eyes. An enormous beard sprung from his face. It made him seem powerful. Don’t go trawling around on websites, he said. Bring reality to life in your mind. Think of the way things felt. His eyebrows flared upwards. Think of the lighting. Think of the smells. Were they sweet? He sniffed deeply. Were they rich? And what did it sound like? Remember these things! His clenched fist struck the podium. You must! By using your imagination to self-arouse during masturbation you can vastly reduce your risk of Alzheimer’s.