Popcorn, from one state to another, from a state you usually think is inedible to a state you think is edible. Popcorn represents sweetness and warmth in love. Popcorn tastes very sweet. Some shape like snowflakes, but it tastes warm. It is estimated that the boy means: Although Christmas Eve is very cold, it feels sweet and warm with his girlfriend.
Popcorn is the symbol of your transformation, the state you are about to transform into and release. There is a song "love is like popcorn", as the lyrics sing: love is like popcorn, which explodes. If love doesn't explode, it can't tell true from false. Love is like popcorn. We both like it, which represents love. Love is like popcorn, warm and sweet.
Source: @bastardvlado