Begin by popping your popcorn as directed on the bag. Set aside.
Put your white chocolate chips in a microwave safe bowl with 1 teaspoon vegetable oil. Melt your white chocolate chips in the microwave in 10 second bursts making to stir in between. Be very careful not to heat the chocolate chips too quickly or they can cause the chocolate to freeze up. It will be hard, look curdled and be unusable if it freezes.
Pour half of your popped popcorn into a large bowl. Pour over half of the melted white chocolate. Use a spatula to stir it to combine.
Pour the rest of the popped popcorn on top and spread the rest of the white chocolate over the popcorn evenly. Allow to cool and white chocolate to harden.
Sprinkle in your M&Ms and sprinkles. Stir to combine. Once the white chocolate has cooled sprinkle a few additional M&Ms and sprinkles.