^ Haha, true.
Miku: "I'm like that last piece of cake. If you don't hurry and make it yours, someone else will come and steal it from you! And then you'll regret it, thinking that that cake could have been yours if you have been more decisive!"
Kyouko: (gets anxious and flustered and buys the last piece of cake)
Then the shop employee brings a whole new batch of freshly made chocolate cake, dozens of pieces of it. Following the analogy, this means that, if Kyouko bides her time and doesn't hurry to make her pick, she'll meet in the future dozens of girls fresher and more delicious than Miku to choose from.
Lucky for Miku, Kyouko didn't seem to realize this. Talk about fail, lmao.