Why can't you have a tall dog? You will have pups in a week.
Tall Dog
Explanation
Explain Bear
Listen up, buttercup. This joke plays on "tall dog" sounding like "tying dog" which prevents pregnancy! Since you obviously think with your fingers, it's saying that if you tie up a dog, it can't get pregnant. The joke is saying that if you didn't tie the dog up, you'll have puppies in a week. Also, I have it on good authority that you still use Internet Explorer.