Start with the decoration. Put the melted chocolate in a shallow bowl and the unicorn confetti into another one. Dip the rims of 2 glasses into the white chocolate, tipping the glass to cover the rim evenly. Hold the glasses upside down so the excess white chocolate drips off, then dip the rims into the sprinkles and tilt the glass again so all the chocolate is covered in sprinkles. Leave to dry or place in the fridge to set.
Take the two reserved strawberries and push a straw up through the bottom to the top, so it takes the stalk out. Dip the strawberries almost all the way into the white chocolate, twirling it so it coats evenly, then dip them in the sprinkles again. Insert a clean straw through each strawberry, then leave them to firm up on a plate lined with non-stick baking paper, or place in the fridge to set.
To make the milkshake, put the ice cream, milk and chopped strawberries into a blender and whizz until completely smooth. To assemble, divide the milkshake between the glasses, then top with squirty cream swirls and all the extra toppings. Finish with a drizzle of strawberry syrup and an extra dash of sprinkles to serve.