Unconsented intercourse that is technically construed as rape.
When performed on your girlfriend, it's surprise sex.
When performed on an even hotter chick, it's rape.
Surprise sex is the reason that children occur in the animal kingdom. Male rabbits rape the females. Yes, really, my sister breeds rabbits and knows all.
Sarah was walking down the road when all of sudden rob jumped out of a bush.
'SURPRISE!' he shouted, he then had a shag with her in that very bush. Good old Surprise Sex.
Aren't birthday parties or presents better when you don't expect them? Surprise Sex also a fantastic method to meet new people and interesting people like hot women or the police. Just ask Bill O'Reilly, he has been engaging in the practice of 'Surprise Sex' for nearly 20 years.