Mash the bananas in a large mixing bowl until smooth and lump-free. This ensures a tender texture.

Pour the sweetened condensed milk into the mashed bananas and whisk until fully combined into a thick, pudding-like mixture.

Gently fold in the self-rising flour with a spatula until just combined. Avoid overmixing to keep the bread moist.

Grease the slow cooker insert lightly. Pour the batter into the slow cooker and spread evenly.

Cover and cook on low for 2 hours. Check after 2 hours; it may need up to 30 minutes more. The bread is done when a toothpick inserted in the center comes out clean.

Allow to cool in the slow cooker for 10 minutes, then transfer to a wire rack to cool completely before slicing.