Summer has arrived in Rio de Janeiro, and away from the city’s beaches, business is booming in the rooftop tanning salons in the city’s low-income neighborhoods. On these sun-soaked terraces, which look out over the city and are full of women of all ages and sizes, the most popular accessory is electrical tape.

This strange look is the secret to getting perfect bikini tan lines in Rio. But not everyone likes it. Dermatologists are not fans of the practice, and some Brazilians think tape tan lines are tacky and even vulgar.

To get the perfect marquinha de fita (“little tape mark”), you need to follow a few steps. First, you put the electrical tape directly on your body. Then, you sunbathe carefully to get clean-cut tan lines.

A session at Cardoso’s salon costs 50 reais (£8), including the tape bikini (and, on some days, a breakfast buffet). For an extra 20 reais (£3), women can have a “moon bath” treatment to bleach their body hair. UV sessions are also available but are more expensive and, in Cardoso’s opinion, less effective for getting a “nice little mark.”

Those who like tape-tanning say it makes them look better. “My crush is asking if I’ve done [my marquinha],” says Ana Caroline Custódio, 27, a customer who is now Cardoso’s assistant during the busy period before Christmas.