Add the water and strawberries to your blender and blend until smooth
Add ice and oats and pulse the blender, making sure the blender does not get hot. It's okay if there are some oat pieces.
Pour oat mixture through a mesh strainer into a bowl with a spout or a pitcher.
You will need to scrape the bottom of the strainer with a spoon if it gets backed up.
Discard the sediment in the strainer, rinse the blender then strain the mixture back into the blender.
Strain the mixture into the rinsed bowl, discard the sediment which is mostly strawberry seeds, rinse the blender and strain back into the blender. Stop here if you want plain strawberry oat milk.
Add the cocoa powder if you want to make your milk into chocolate covered strawberry oat milk and blend. No more straining needed!