The narrator and the other black boys involved are lured to the site of the Battle with other bait--for instance, the narrator has been told he is there to read his essay/speech which is deemed the best at his school. He is lured there with the hope of impressing the white audience with his intellect and writing ability and ends up wrestling and wallowing around half-naked on an electrified mat for a few coins. It is painful and humiliating to the boys since they are the source of entertainment for the white men who are present. The men guffaw loudly at the sight, especially when they boys are shocked as they pick up the electrified coins.
To make matters even worse, there is a naked white woman who is dancing--also a source of entertainment for the men. The boys are forced to look at her and are both embarrassed and sexually aroused which angers them. During this time period, looking at a white woman the wrong way period could cause them great danger--to be forced to look at and be attracted to this naked woman puts the boys in a very precarious situation.
All these emotions put the boys in a very raw psychological, emotional, and mental state. They are vulnerable in their humiliation, but understand that there is nothing they can do about it. The white men have successfully dehumanized these boys.