Joke I got from Jumbo Joke:
My girlfriend and I had been dating for over a year and we decided to get married.
There was only one thing bothering me, very much indeed. That one thing was my finance's younger sister. My prospective sister-in-law was 20 years old, wore tight mini skirts and low cut blouses. Once my girlfriend announced our plans, her sister would regularly bend down near me and I enjoyed many pleasant views. It had to be deliberate -- I didn't notice her doing this near anyone else.
One day the sister called and asked me to come over to check the wedding invitations. She was alone when I arrived and whispered to me that soon I was to be married, and she had feelings and desires for me that she could not overcome. She told me that she wanted to make love to me -- just once -- before I got married and committed my life to her sister.
I was in total shock and couldn't say a word.
She said, "I'm going upstairs to my bedroom, and if you want to go ahead with it just come up and get me."
I was stunned. I was frozen in shock as I watched her go up the stairs. When she reached the top, she pulled down her panties and threw them down the stairs at me. I stood there for a moment, then turned and went straight to the front door. I opened the door, stepped out of the house, and began walking toward my car.
My future father-in-law was standing outside. With tears in his eyes, he hugged me and said, "We are very happy that you have passed our little test. We couldn't ask for a better man for our daughter. Welcome to our family!"
The moral of the story?
Be smart, like me. Always keep your condoms in your car.