Wiktionary
tympanocentesis
n. The drainage of fluid from the middle ear by using a small-gauge needle to puncture the eardrum.
Wikipedia
Tympanocentesis
Tympanocentesis is the drainage of fluid from the middle ear usually caused by otitis media, by using a small-gauge needle to puncture the tympanic membrane, also known as the eardrum.
Main indication for tympanocentesis is failed treatment with antibiotics
It is sometimes referred to as a "tap" and, when conducted twice as part of a clinical trial of medication, a "double tap."