A man is sitting next to a woman on a plane.  Turns out she's a drop-dead-gorgeous blonde!  When they reached 27,000 ft. the plane leveled out and woman sneezed. 

This would have been perfectly normal but for the fact that after she sneezed she shuddered violently.  About five minutes later she sneezed and once again shuddered violently.  Five minutes later she sneezed and shuddered yet again.

Finally the man had, had all he could take and his curiousity got the better of him.

"Are you O.K." He asked

"Yes," said the woman "I'm fine, why?"

"It's just that three times you've sneezed and three times you've shuddered violently almost immediatly afterwards."

"Oh, I'm sorry," said the woman "It's just that I've got this rare condition, every time I sneeze I orgasm"

"Oh really," said the man and being a keen follower of medical science asked "What are you taking for it."

"Pepper," answered the woman.