Heat season.

It was coming soon, and Rumble wanted to prepare, as did Apple Bloom.

A few hours later, two potions were made and bottled. However, a call by Applejack startles them, causing them to drop the potions.

You can imagine what happens the next day.

When Rumble begins to change on the middle of the next day's class, he needs help more than ever. Well, sometimes help comes to you at the oddest times.

A partial adaptation of Hot Swap, by Cosmonaut, with elements of The Definitive Guide to Pony Anatomy Starring Princess Celestia and Princess Luna, by Pen Mightier.

Kinks: Potions, genderswap, lactation, perhaps more that I'm forgetting.

I'm not great at clop, so forgive me if this isn't exactly high quality. This was just another random idea.