Combine all ingredients in a medium saucepan over medium-high meat. Stir frequently to dissolve the sugar.
Bring the mixture to a boil and reduce to a simmer. Simmer 5 minutes; smash the raspberries with a mixing spoon or whisk while simmering to break them up. Remove from heat and allow to steep until cool (approximately 1 hour).
Strain through a fine mesh sieve and keep sealed in the refrigerator for use.
Rimming the Glass with Pop Rocks
Pour the pop rocks into a shallow saucer or other small plate.
Pour some of the raspberry simple syrup into a bowl large enough for the top of the glass to fit into.
Turn a glass upside down and touch just the top of the glass opening to the simple syrup; enough to moisten the rim only.
Place the glass opening down in the plate of pop rocks and rotate from side to side to coat with pop rocks. NOTE: The pop rocks can gently be pushed toward the outside of the glass to aid in coating.
Place the glass, still upside down, onto a clean surface and allow to sit for the pop rocks to dry onto the glass (approximately 10 minutes). This aids in the adherence to the glass.
Instructions for Love Potion Number 9:
Add 6-8 red hots (or if you find larger heart shaped red hots as shown in the photos, use 2) in the bottom of each glass.
Add the raspberry simple syrup and fill with ginger ale (NOTE: do not fill up to the pop rocks or they will begin to explode).