It is easy to assume an egg-free batter is safe to taste. Ordinary flour is a raw ingredient and can carry harmful microorganisms, so removing eggs does not remove that risk.
Bake or cook flour-containing mixtures according to appropriate instructions. Do not rely on improvised home heat treatment to turn ordinary flour into a reliably ready-to-eat product. For a dessert intended to be eaten without baking, use a recipe and commercially suitable ingredients designed for that purpose.
Keep raw flour and dough away from ready-to-eat foods, and clean hands, utensils, and work surfaces after handling them. Children helping in the kitchen need the same clear distinction between ingredients to cook and food ready to taste.
If you want to check sweetness while developing a recipe, do not sample raw batter casually. Use a properly cooked small portion when the method allows it, or work from a reliable recipe.
Further reading: FDA: flour is a raw food.