Noun: Slang which is a bastardization of the words
ear and
orgasm, intended as a compliment to music that stirs the
loins and brings about
warm fuzzies in all the right places for a human being that appreciates the best music. A song is only an eargasm if you personally listen to it a lot and get great satisfaction out of it, predominantly while using headphones. If it puts a
cheshire cat smile on your face, it's an eargasm.
The descriptive adjective form is eargasmic.