The organisms that cause yeast infection produce secretions that are irritating to the genital tissues. The nerve endings that sense the presence of the yeast are located at the vaginal opening. Although you may have an infection inside the vagina, you can often get symptomatic relief simply by frequently washing away the secretions with water until your chosen treatment knocks out the infection.
While yeast is usually passed between sexual partners, it can also be passed to others, including children, through activities such as shared baths. To ensure you're not passing yeast, avoid bathing or sharing towels or bathwater with your children; wash your hands frequently -- and always after using the bathroom -- with soap and water; and wash your clothing in hot water. The high water temperature in your washing machine should destroy any yeast organisms on your clothes. But if you want to be sure they're all gone, add a cup of white vinegar during the rinse cycle.
You should also wash up extra carefully before lovemaking and should ask your sexual partner to do the same.