1. Secret rites, especially those connected with the worship of Dionysus or Bacchus.
2. An occasion of feasting or revelry; especially, one characterized by excessive drinking and indiscriminate sexual activity.
3. Any act of excessive or frenzied indulgence; binge, splurge, spree, fling.
4. An occasion of excessive indulgence in any activity, attitude, condition, etc.; an excessive or extravagant display of something. Frequently used with of.

Secret rites in the worship of certain Greek and Roman gods, especially those of Dionysus and Bacchus, celebrated with wild dancing, drinking, etc.; borrowed from Middle French orgies, learned borrowing from Latin orgia, and borrowed directly from Greek orgia, plural, secret rites.

The figurative sense of wild excess (as in an orgy of blood) is first found in 1883.

Dictionary of Etymology

Other examples of the figurative sense of wild excess:
1. The protest degenerated into an orgy of looting and shooting.
2. When he got his first salary check, he indulged in an orgy of spending.