Can you imagine what you could do with two girls at the same time? It'd be insane. You could play Mario Kart and have room for one more friend to join. You could play Twister and have one person be the spinner. You could build a two-level human pyramid. The possibilites are limitless!
And by the way, they're incredibly hot twins. You know what that mean. TWO BIRTHDAYS AT THE SAME TIME!