Mash 3 ripe bananas. Mix in 1 cup peanut butter. Add 1 (32 oz) container of plain yogurt. Mix all together by hand, until blended. Pour in either ice cube trays, or small plastic cups (disposable) put on cookie sheet and freeze. Once frozen put in zip lock baggies for quick doggie treats. If you would rather, you can just put mixture in ice cube trays and freeze.