(adj) To relax under the spell of an unusual buzz from a previous cannabis consumption session that was several hours earlier. Or in other words "Marijuana hangover".
Tony: Damn man we packed a Hookah with some BC Bud last night and I'm still Space Chillin.
Doug: Dude are you foreal? It's been like 15 hours since you smoked?
When a person is just hanging out yet still dresses tactically. Usually in a very incognito military fashion to be ready for any defensive maneuver/assault.
Sometimes you can find me tacti-chillin' in the most tropical of third world countries.