This moment is complicated to explain because there's an important cultural thing happening.
It's very common in the Western culture for close friends to tease each other. Sometimes it even sounds like friends are being very mean to each other- insulting each other, calling each other rude names, even swearing at each other. However, this is common and considered friendly, but only if you are so friendly that you are 100% sure the other person really does like you (so again, usually close friends.)
There is a similar thing when a guy and girl want to flirt with each other. Sometimes, they will do things that seem a little rude or harsh: lightly make fun of each other, tease each other when the other messes up, etc. Often this transfers into getting more comfortable with each other because you can pretend to be mean as a playful way to touch each other and get more familiar: bumping into each other as you walk, maybe throwing a bit of food at the other, pushing each other, etc. The idea is to be only mean enough to be playful without making anybody really angry (maybe I'll touch my ice cream to your nose because it's easy to clean up, but I won't put it on your clothes).
In this movie scene, Denise was trying to flirt and be playful in this way, but went to far and annoyed Drew. It's an excellent example of Western culture the includes relationship dynamics, sarcasm, maybe a bit of slang, and you learn about some food dishes as well.
Excellent question, maybe one of the best I've ever seen here on iTalki so far. Hope that helps.