Add all ingredients to a high speed blender (see notes if you have a regular blender) except the oreos. Blend until smooth. Using the tamper tool that comes with a vitamix really helps, but if you're having trouble blending, just add a bit more milk as needed. I like it pretty thick, so it will be thick as written, don't hesitate to add more milk if you prefer it more like a smoothie consistency! If you are using gluten free oreos, they will thicken the milkshake up quite a bit, so make it just a smidge thinner than you think you should.
Blend until completely smooth.
Taste and adjust flavors as desired. If it's too thick, just add the milk or even more as needed, but if it's not thick enough, add in a handful of ice. Add in the oreos and pulse just to combine.
To make the drizzle/magic shell, add the coconut oil and chocolate chips to a bowl and microwave in 30 second intervals, stirring in between until completely melted. This should take only 2-3 intervals.
Drizzle into glasses and then pour in the milkshake. Top with coconut whipped cream (essential!) and more of the chocolate drizzle plus a few crushed oreos.