FWIW it's just a nickname for their apparently dangerous design (which doesn't necessarily translate to actually dangerous), it has nothing to do with suicides.

In pretty much every other country, this is illegal and against code because it is considered very unsafe. But somehow it seems to work for Brazil, Turkey, and a bunch of poorer nations.

It doesn't (usually) kill the users due to a bunch of clever design and good luck, which goes like this:

* The power grid provides two wires. "Live", normally around 220 volts AC (110 in usa), and "Neutral", usually near zero - perhaps 5 volts AC. The Earth is at 0 volts AC, and is connected to all your water, pipes, plumbing, metal things in your bathroom, etc.

* Normal devices like light bulbs allow electrons to flow between Live and Neutral, but should not allow electrons to flow to Earth. Normally, if flow to earth is detected, a GFCI/RCD will switch everything off for safety, since a human might be on that path!

* The resistance of a wet-skinned human is such that if 5 volts AC is put across them, they'll barely feel it, but if 220 volts AC is across them, they'll probably die.

* This shower relies on connecting Live (220V) to the water, and also connecting Neutral (~5V) to the water. That causes electrons to flow through the water, and it to heat up.

* However, the connections are arranged so that the neutral is far closer to your head than the live - so the voltage your head sees is perhaps only 5 volts relative to the Earth (and the wet floor you're standing on). You feel the tingly electric-water, but you don't die today.

* But the big risk is that if the neutral wire were to fail anywhere between the shower and the power station for any reason, now the water you're standing in becomes Live at 220V and you die today.