First, fill your syringes with Aperol and set aside. You can store these in the fridge to keep them cold!
If you want to add a bloody rim, you can use a homemade blood orange syrup. Simply pour a small pool of syrup on a plate and twist the rim of the glass in the syrup. When you flip the glass right-side-up, let the syrup drip down the sides like blood.
Then, fill your rimmed glasses with ice.
Pour in 3 oz of Prosecco first, and top with 1 oz of sparkling or soda water.
Put the syringe directly into the wine glass, but don't add it yet. You can let you guests push in their own shot of Aperol.
Garnish with a fresh orange slice and serve immediately.