For a long time I thought this was just a non-sequitur homerism, but I learned that the original intent of the joke is that someone with long hair stepping out of the shower will put a towel around their head to hold their wet hair, which covers their ears and makes it harder to hear the phone. I still like it as a weird-twitter-esque nonsense gag, but the intended meaning is also a great joke, and both feel very Homer-coded.