What is the meaning of the quote? “Roger took up a small stone and flung it between the twins, aiming to miss.” (Chapter 11 pg. 175)

Roger is still held back by the customs of the old world. He aims to miss because somewhere in his subconscious he recalls reprimands from adults. He aims to miss the twins but soon Roger will understand that there are no adults to scold him and any hesitancy he had from memories will quickly disappear.