Eunice, a London-based travel nurse, recently shared some advice – you can determine how helpful it is – on TikTok.

The clip, which has been viewed more than 3 million times, shows Eunice standing in front of your average public bathroom sink.

“I don’t know if I’m a moron, but I was today years old when I learned that clicking this,” she says pointing to the push faucet, “depending on the seconds depends on how long the water comes out.”

She then demonstrates by holding the faucet down for several seconds while the water gushes out of the faucet. When she releases it, the water continues to flow and she washes her hands.

“No one ever told me that sh*t.”

Apparently she wasn’t the only one who wondered how these types of bathroom sinks worked.

“This is life changing,” one user wrote.

While another thanked her for “teaching us valuable lessons.”

However, not everyone was impressed with her life hack.

“So we just have to waste water for the first 8 seconds?”

Someone else offered another possibility, “It’s not the time, it’s the pressure you put on it.”

According to Commercial Washrooms, “many non-concussive taps will allow you to adjust the timing for the water flow, whereas some push taps will specify their flow time.”