What is "heavying"

Usage examples of "heavying".

It was a reddish-brown rock about the size of a tennis ball that looked exactly as though it had been hastily painted, and I had to wait a minute, my head heavying even more, before I knew what it meant.

Clouds gathered in his eyes, heavying them, but they were glittering with something intensely new.

The games and contests were all over now, and partly as a consequence of that the drinking was heavying up as the last scraps of food were being eaten.