When you touch someones nose with the index and or middle finger. It is a huge commitment. Basically proposing.
girl: omigawsh he tried to use The Nose Boop on me!
guy: what a creep
girl: ikr!!
When a creep from your theatre class touches this girls nose and she doesn't want it because its too much commitment; basically proposing.
girl: omigawsh he tried to do The Nose Boop on me
guy: he's been watching too much twilight