One party can obfuscate meta data by, for example, using a "burner phone" or by routing VOIP calls through 7 proxies.

The only way to obfuscate the content of a call is if both parties agree in advance to speak in code.

"Hi honey, the sparrow has left the nest. There may be a bee in the bathwater."

"John is that you? What the heck are you talking about? How did the cancer test go?"