Also known as "Theo Voice." This is when someone uses (usually inadvertently) a low sultry voice during a serious moment that sounds like those Radio Dj's who take the overnight shifts. It comes from the Los Angeles based Adult Contemporary Station KOST 103, as well as the old famous Los Angeles R&B radio host "Theo" from 92.3 the Beat.
guy 1: Hey remember when we spontaneously drive to Huntington Beach that one night last summer. I really enjoyed that man
guy 2: Whoa whoa relax, you slipped into your Kost Voice for a minute there man