Meaning:
Lit. “to go onto/start a tango”, which in most cases describes a multiday drinking binge in different bars, dance clubs or house parties. What might be included as well is consumption of illegal drugs and one night stands with random people met in those places. To go on a bender.
When you say that someone “poszedł/poszła w tango”, his or her colleagues should not expect their presence at work. If the person in question is an alcoholic then the binge usually has very negative consequences for their health and social life as well.