Use a knife to spread about 1 teaspoon of marshmallow fluff onto one pretzel. No need to coat the pretzel! Press another pretzel into the top of the fluff to make a sandwich. The marshmallow will be well spread out by this point. Place on a tray lined with wax paper. Repeat until all marshmallow fluff is used; you'll get about XX number of pretzels.
Place pan in the freezer for 20 minutes.
Place chocolate chips in a glass bowl along with 1/2 tsp coconut oil. (You can omit the oil if you're using melting chocolate discs.) Microwave on high for 1 minute 30 seconds. Let sit in the microwave for an additional 2 minutes. Stir gently, then return to the microwave for 15 seconds, if needed.
Remove the pan from the freezer.
Dip each pretzel sandwich into the bowl of chocolate, gently tapping the edge of the bowl to release excess chocolate. This process is so much easier when you use a dipping tool! Lay the covered pretzels down on a piece of wax paper. Top with sprinkles, if desired.
Repeat the process until you have covered all your marshmallow pretzels, re-heating up the chocolate as necessary.
Place white chocolate in a small baggie and microwave for 40 seconds. Let sit 2 minutes, then knead bag gently. If chocolate is still lumpy, return to the microwave for about 10 seconds. Snip the corner of the bag and drizzle chocolate over pretzels.
Let cook to set. Store in an airtight container to save.