'Jabangr' is an abbreviation of the question: 'did you bang her?' It is used as an immediate response to friends of yours who are talking about various girls/women they've met and/or been on dates with. It's not important whether or not you care about the person actually banging the girl.
Unlike the actual question--"did you bang her?"--which is intended to elicit an answer--the abbreviated phrase is used more as an interjection designed to introduce the thought that maybe you should have thought harder about trying to bang the girl.
Paul: "So I met this girl last night..."
Paul: "Ha, no we had dinner, but then afterwards one of her friends showed up, and..."
Paul: "Man, what a panoche you are."
mystical in nature, and of an ineffable style, given one's totally baked reference frame at the time.
originally derived from a switch around of the phrase "magical mystery tour" such that "mystical magery tour" is uttered instead.
essentially, one must be in a uniquely high state of mind to arrive at such a turn of words, and therefore using the word 'magerous' connotes a supreme sense of wonder at events as they are beheld/unfolding that signifies the classic slowing of time due to the onset of being quite high.
alternatively, 'magerous' may be an apt descriptor of any such event, person, action, or sequence of events that cannot be immediately comprehended due to its dumbfounding nature.
that party we came across last night while high on the peyote you scored can only be summed up as magerous.