on a tear

Short definition from Wiktionary

Prepositional phrase

1. 1
   Engaged in a continuous, fast-paced procession of actions or events, especially with favorable results.
2. 2
   In or into a protracted state of agitation, fury, or zeal.
3. 3
   Binge drinking; engaged in a bout of heavy consumption of alcoholic beverages; on a bender.