flash on something
flash on
1. To abruptly turn or go on, as of lights. As the man laughed manically, the lights in the haunted house flashed on, and we all ran out, screaming.
2. To illuminate someone or something. I repositioned my lamp so that it flashed on the things I'd dropped behind my bureau.
3. slang To think of or recall something. It took some time, but we finally flashed on a solution to that problem.
flash on something
in. to remember something suddenly and vividly. I was trying to flash on it, but I couldn’t bring it to mind.