The full sentence from "Bernice Bobs her Hair" is: "She did not know that had it not been for Marjorie's campaigning she would have danced the entire evening with one man; but she knew that even in Eau Claire other girls with less position and less pulchritude were given a much bigger rush."
The phrase "given a much bigger rush" is meant as "awarded significant attention."
In this text, the main character, Bernice, is thinking about her lack of popularity in society. She is wondering why she does not get more consideration from people (men in particular) at parties. However, her reasoning is that young women who spend their time surrounded by men even though they have lower social status ("less position") and don't look as good as Bernice ("less pulchritude") are cheapening themselves for attention.
