an inerjection meaning "Relax! I'm only kidding!" especially once you realize you've gone too far in kidding around. The type of lingo that is especially suggestive of sickos or whackos.
"Don't look at us while we're defecating, if you know what's good for you,little kid!" Kenny, Harun, Hai, and Hamilton threatened. "Psyche!"
they said, with sick grins, as they saw the little kid was about to bawl.
"A jacket is better than an overcoat, because you can moon people with your coat on, that way!" Jamie, Matt, and Robert told Mike and Eric. "Psyche!"
they then exclaimed, with derisive grins, as Mike and Eric stalked off.