Preheat oven to 300 degrees.
Place 5 unwrapped root beer barrels on a baking sheet lined with a silicone mat or parchment paper. Leave lots of space between the root beer barrels, so that there is space to spread and so that you can add a lollipop stick.
Bake the root beer barrels for about 12 minutes at 300 degrees. Remove from the oven and quickly put a lollipop stick into each melted candy. Give the lollipop stick a gentle twist to wrap the melted candy around it, ensuring it really stays in place.
Working quickly, shape the hot candy into a mug shape using a thin knife. You want the sides and top of the mug to be somewhat flat.
Quickly pull some of the hot root beer barrel to one side, forming a handle. Press the candy above and below the handle back towards the center to make the side of the mug. This really helps to make it look like a root beer mug.
If the candy hardens before you can do the all of the shaping, simply return it to the oven to soften again.
Melt the white chocolate chips or candy coating in the microwave.
Dip the tops of the root beer float mugs in the melted white chocolate or candy coating. Place them back on the silicone mat to harden.
Cut small segments of brightly colored, gummy candy strings for straws. Attach with a little of the melted white chocolate or candy coating.