I’m looking for this children’s book about two sisters. Big sister must take little sister out to play while mom is busy in the kitchen. Little sister sings “We’re going to the rocksy-tocksy-wocksies” as they head to the shore to play on the rocks. Little sister slips and falls but big sister rescues her. My daughter checked this book out of the elementary school library around 1989-1992, but it had been published well before that. Thank you.