• In a blender or food processor blend chocolate ice cream and milk until smooth.
• To line the glasses with chocolate sauce - Use chocolate sauce that has a nozzle or is in a squeeze bottle.  Place the tip inside the glass, about 1 inch from the top.  Gently squeeze rotating the glass until you have a line all the way around.  When you stand the glass up the chocolate will drizzle down the side. 
• Pour milkshake into prepared glasses.  Top with whipped cream and sprinkles.

To make the whipped cream

• Beat heavy cream until soft peaks. Mix in sugar and vanilla.  Beat again until stiff peaks.