There were no loose energized cable ends in this story, fyi. The light strip was your standard white LED tape cut in the middle of the copper pads [0]. I soldered the USB cable's power leads to the copper pads [1] and then covered the solder joint with heat shrink tubing filled with liquid electrical tape [2]. Then on the strip I connected to, it was the same procedure but with a female USB-A connector. There were no conductors with exposed ends to move apart and make a spark.

[0] e.g. https://www.homedepot.com/p/32-8-ft-LED-Tape-Light-120-LEDs-...

[1] https://www.homedepot.com/p/Star-brite-4-oz-Liquid-Electrica...

[2] hero image from https://us.govee.com/blogs/led-strip-lights/how-to-solder-le...