What does he mean by aahh stage?

Informative if you're a fellow pork enthusiast, worth it even if you're not just for this paragraph:


My first thought, however, on being introduced to ours, was how on earth we were going to get them in the back of the car. Possibly taking Tony’s advice on costs too far, we had decided against hiring a van. These four were three months old, not two, and well beyond the aahh stage. Judging by the tussle, just young enough, too, to be rolled through the hatchback two-by-two after Caroline had hoisted them by the back legs while I grabbed the front. A struggle, but worth it for the looks on fellow motorists’ faces as the pigs stared out of the back window at them. Not to mention the expressions as we pulled up at an Indian restaurant to shut the back properly.


More Intelligent Life: Pig Farming and the Tamworth Four