Why do I have a feeling Pinkie literally sat him down, slapped a hat on him, crammed the noise-maker in his mouth and said "Now blow really hard to spread some New Year cheer! Oh-oh-oh-oh! I know just what to do! I'll go grab the rest of your hive friends too and then swing by Octavia's place and drag her out of bed so we can start a New Year's Changeling Noise Maker ORCHESTRA!!!"



Then she dashes off, he's left just sitting there looking around at either an empty room or anypony else who's in there, horribly confused, but then just shrugs and blows the noise maker anyways.