How to never waste your first use of Manaflow Band

Are you tired of your first spell cast in a lane consuming your Manaflow Band, despite you already being at full mana?

Well, do I have a solution for you.

Step 1: Never cast a single spell, only farm through auto attacks. Step 2: Purchase a Tear of the Goddess, but never cast spells to fill it. Step 3: Upgrade to a Manamune, and use your autoattacks to fill the mana bar. Step 4: Now that your Manamune is a Muramana, it will consume mana on attack without consuming your Manaflow Band. Step 5: Auto attack champions a few times, now that your autos consume a small amount of mana. Step 6: Cast a spell to use your Manaflow Band, therefore, not wasting your first usage of it. Step 7: Profit.

Or, I suppose you could just cast a spell around the 1:15 mark, so your Manaflow Band will be ready at 2:15, when you've actually spent your mana.