Breathe the pressure

Something tingled in Castillo's neck. And his chest.

It took him a while to figure it out, of course. Not that it was entirely his fault.

It's not every day you grow gills.

It's not every day your lung capacity magically expands.

Along with his chest.

Especially two points.

The hands on his hips shifted their grip, on account of the expansion. The strange new muscles bunching and stretching under his skin.

And he knew, he knew he was becoming something...special.

As Castillo's change progressed, he stretched his fingers and toes, just to feel the sensation of webs stretching between them.

Strange, blue-green fins traced the curves of his shoulders, and down his back.

When his tail erupted, and curled itself around his backdoor botherer, twin fins adorned the end of it.

Even his dick was becoming streamlined and smooth. Perfect for an aquatic environment.

But not limited to it.

When his hands swelled, and snapped his belt, he didn't try to go anywhere. He just grabbed the sister in front of him, and thrust her into him even harder.

There was nothing but her joy at being used.

And, of course, the thoughts of all the people she'd soon share it with.