In a large bartender shaker add both vodkas and grenadine along with only a few pieces of ice

Shake well to combine

Fill your glassware 3/4 of the way full with ice

Now add your Vodka mix and fill ONLY 1/2 way

Rinse your shaker with water

Now add the Blue Curacao and sprite

Shake well to combine

Use a large serving spoon upside down hold it above the glass and slowly pour the Blue Curacao mix into the glass.

You are pouring the mix directly onto the spoon and letting the liquid drain off the spoon into the cocktail glass

If you do it slow it will not mix.