Air quotes are the finger
gestures many people use to meta-communicate that the spoken
word they are air quoting should be heard in
inverted commas.
This gesture, much loved by Generation X, involves holding fore- and second-fingers (of both hands) just above ear height, and twitching the fingers down once or twice in syncopation with the word being air quoted.
The gestures can be exectued in an extravagant way, or in a more restrained way, depending on the degree of cool that the air quoter is attempting to communicate.