It's a bubble of snot coming out of your nose. There's also a smelly version if the person has COPD.
Erin has fun with Marco, a slob of a beast with Chronic Bronchitis. ERIN: "Do it again! Do it again! "Marco makes a booger bubble that dislodges and floats aboot the room. Erin pops the bubble and makes a face like something smells. ERIN: "Ew! Something smells." Marco laughs uncontrollably until he codes and dies.
by Terio Marin November 2, 2016