He stood first on one foot and then on the other, and suddenly screwed up his face and put his knuckles in his eyes and sat down on a heap of stones by the roadside.

When we pulled his hands down he was actually crying.

The author does not wish to say it is babyish to cry.
'Whatever is up ?' we all asked, and Daisy and Dora petted him to get him to say, but he only went on howling, and said it was nothing, only would we go on and leave him, and call for him as we came back.
Oswald thought very likely something had given Denny the stomach-ache, and he did not like to say so before all of us, so he sent the others away and told them to walk on a bit.
Then he said, 'Now, Denny, don't be a young ass.

What is it?
Is it stomach-ache ?' And Denny stopped crying to say 'No!' as loud as he could.
'Well, then,' Oswald said, 'look here, you're spoiling the whole thing.
Don't be a jackape, Denny.

What is it ?' 'You won't tell the others if I tell you ?' 'Not if you say not,' Oswald answered in kindly tones.
'Well, it's my shoes.' 'Take them off, man.' 'You won't laugh ?' 'NO!' cried Oswald, so impatiently that the others looked back to see why he was shouting.