I was a very happy man. My wonderful girlfriend and I had been dating for over a year, and so we decided to get married.
There was only one little thing bothering me... It was her beautiful younger sister.
My prospective sister-in-law was twenty-two, wore very tight miniskirts, and wore extremely suggestive outfits. Worse yet, she would regularly bend down when she was near me, and I always received an eyeful in return. It had to be deliberate, because she never behaved this way when she was near anyone else.
One day my fiancee's 'little' sister called and asked me to come over to check the wedding invitations. She was alone when I arrived, and she whispered to me that she had feelings and desires for me that she couldn't overcome. She told me that she needed to have me just once before I got married and committed my life to her sister.
Well, I was in total shock, and couldn't say a word.
She said, "I'm going upstairs to my bedroom, and if you need one last fling..."
I was stunned and frozen in shock as I watched her go up the stairs. I stood there for a moment, then turned and made a beeline straight to the front door. I opened the door, and headed straight for my car.
Lo and behold, my entire future family was standing outside, all clapping!
With tears in his eyes, my father-in-law hugged me and said, 'Son, I can't tell you how pleased we that you have passed our little test. We couldn't ask for a better man for our daughter... a man with more integrity than you. Welcome to the family."
And the moral of this story is:
Always keep your prophylactics in your car.
Cue the rimshot.