They had been dating for over a year. He was an excellent boy, with a promising future; she was beautiful, intellingent and talented. They liked each other very much and everyone used to say they were made for each other. So they thought about getting married. Their parents friends and family applauded their decision. There was only a cloud in the horizon: her younger sister. Twenty years old, the girl adopted provocative poses in front of him - got very close to him, leaned forward while wearing a mini-skirt, stretched on the sofa alluringly...
One day, she asked him to help her mail out the wedding invitations. She was alone when he arrived. Soon after, she whispered that she was sorry he was going to get married so soon and admited that she was attracted to him. She asked him if he wouldn't like to sleep with her before getting forever attatched to her sister. He was shocked. She kept on: I'm going to my room. If you're interested, come with me. Upon saying that, she went upstairs. When she arrived on the first floor she got undressed and threw him her underpants.
The guy was gobsmacked, unable to utter a single word. This could not be happening! He was paralysed for a moment. Then he went towards the door, opened it and ran towards his car, which was parked across the street. Outside, his future father-in-law, with tears in his eyes, hugged him saying: I am so happy you resisted temptation and passed this test. I'm sorry, but I needed to know you were the right man for my daughter. Welcome to the family, son!
Moral of the story:: always keep your condoms in your car.