"Guys only dare to try unusual hairstyles when mass enthusiasm breaks out and there's some big event on like the Cup," observes Stefanie Koehn, president of the German hairstylists' association in the central city of Goettingen.
Demand for "really weird styles" of dyeing surged after the tournament began.
Most women customers valued their own hair too much for bizarre experiments and preferred to apply black, red and gold to their faces as make-up, Koehn says. Colour sticks that can be applied to both skin and hair and then washed out were selling well.
"At first, girls usually put just a teensy little dab on the cheeks, but then come back for more sticks," comments Wolfgang Tasche of the city of Hanover's hairdressers' association. Men have fewer compunctions against plastering themselves in colours of flags.
"We had one guy in here who got us to shave practically his entire head and then paint it in the German colours," Tasche says.
Koehn believes Germans copied the idea from Brazilian fans, whose team is the reigning title-holder. Many young Germans may perceive painting the head, chest and other body parts as part of the magic needed to win.
"They're not concerned about looking beautiful. They just want to declare their loyalty to Germany," says Koehn.
At Heiko Klunker's hair salon in the city of Bremen, colours are also a big seller.
"We have templates to paint them on the head. A lot of guys are asking for mohawk hairstyles in the German colours."
The mohawk, also termed "iroquois" in many European nations, requires both sides of the head to be shaved, leaving a strip five to eight centimetres wide down the middle of the head to be spiked up or fanned out. It was popularised by street punks.
"The mohawk is really up to date. It has become mainstream," says Klunker.
Technicolour mohawks are done in non-permanent colours that can be washed out before showing up to work on Monday morning.
Sven, 22, a clerical worker at an insurance company in Hanover, is one of the young Germans in national colours. His hair was trimmed back to a fuzz just a few millimetres long. Each side is coloured black, red and gold.
"I did it to wish our team good luck and because it's so exciting to have the World Cup happening here," he explains. "I'll wash it out before work or else I suppose my boss would tell me off."
With wispy hair, colours look ridiculous, warns Koehn. "A hairdresser will usually make sure a style suits your overall appearance before starting. These weird styles do look awful on some people."
Some customers are adamant, demanding stylists follow odd instructions. "If they insist, we'll do it," she says.
"It's an occasion to do strange things that wouldn't normally be possible." After the tournament, sedate hairstyles will return.
Koehn adds, "I remember at the last World Cup, many customers wanted to copy the hairstyles of famous players. Even today, a lot of guys demand cuts just like that worn by David Beckham."