There once was a lady who was tired of living alone. So she put an ad in the paper which outlined her requirements. She wanted a man who 1) would treat her nicely, 2) wouldn't run away from her, and 3) would be good in bed. Then, one day, she heard the doorbell ring. She answered it, and there on the front porch was a man in a wheel chair who didn't have any arms or legs. 

"I'm here about the ad you put in the paper. As you can see, I have no arms so I can't beat you, and I have no legs so I can't run away from you." 

"Yes, but are you good in bed?" 

"How do you think I rang the doorbell?"