It's a colloquial saying that originated on social media, and it describes this annoying style/trend of singing that today's singers use. Liz Gillies describes it best with this video: @EclecticHams ...
Pop singer Tate McRae's hit "Greedy" is arguably one of the biggest songs of 2023, climbing the Billboard Hot 100 chart and amassing millions of streams on Spotify (over 300 million and counting).