The act of not exactly sitting, but not exactly standing over a LONGDROP, but more a case of just bending the knees with your bum a few inches above the seat when wanting to defecate
To levitate means to smoke pot. It refers to achieving a meditative mindstate, one that yoga gurus (presumably) achieve, whilst sitting in a lotus pose. When in this mindstate, it might feel as you're floating mid-air, ergo levitating.