This guy has always dreamed of owning a Harley Davidson. One day he has finally saved up enough money so he goes down to the dealer and he picks out the perfect bike. While getting all the paperwork together, the dealer tells him about an old biker-trick that will keep the chrome on his new bike free from rust. The trick is to keep a jar of Vaseline handy and put it on the chrome before it rains, and everything will be fine. He happily pays for the bike and leaves.
A few months later, the young man meets a woman and falls in love. She wants him to meet her parents so she asks him to come to dinner. He readily accepts and the date is set. At the appointed time, he picks her up on his Harley and they ride to her parents' house. Before they go in, she tells him that they have a family tradition that whoever speaks first after dinner must do the dishes.
After a delicious dinner everyone sits in silence waiting for the first person to break and get stuck doing the dishes. After a long fifteen minutes, the young man decides to speed things up. He reaches over and kisses his woman in front of her family. No one says a word. Emboldened, he throws her on the table and has sex with her in front of everyone. No one says a word. Now he is getting desperate, so he grabs her mother and throws HER on the table.
They have even wilder sex. No one says a word. He is wondering what to do next when he hears thunder in the distance. His first thought is to protect the chrome on his Harley, so he reaches in his pocket and pulls out his jar of Vaseline.
The father says "Okay dammit, I'll do the dishes!"