As experienced by the dissimulator, the burden of effort may range from grin-and-bear-it at the easiest, through lip biting and muttering, to teeth-grinding determination at the most difficult.
Blackie, him that's Blindy now, and this other boy Willie Sawyer, and they were slugging and kneeing and gouging and biting and I see one of Blackie's eyes hanging down on his cheek.