When you are so excited that your boner is harder than normal. Usually in reaction to receiving a new Apple product, of which said product will probably be outdated in 6 months, making the power of this boner fleeting, but truly powerful. When one becomes "Apple Hard", they often experience a feeling of superiority, usually over people who use PC's. While this feeling of superiority may be misguided, the power of the Apple Hard is often too powerful for the novice and one succumbs to the massive pull of the boner.
My new iPad just came, and I am Apple Hard right now!