CSS, Astoria, London

After almost two years of non-stop touring, you'd think that Cansei de Ser Sexy really would be tired of being so sexy. Having seen the Sao Paulo electro-rock sextet (whose name translates, of course, as "I'm tired of being sexy") several times before, I doubted that the band would have the usual sugar-rush enthusiasm to pull out the stops. But at their headline NME show in London, CSS showed no signs of letting up.

They took to the stage at the positively un-rock'n'roll hour of 8.40pm, a blur of bright lights and shiny red trousers – the latter courtesy of firecracker frontwoman Lovefoxxx, who had done away with her usual multi-coloured, layered catsuits in favour of an equally eccentric get-up. Lovefoxxx, aka Luisa Hanae Matsushita, is CSS's not-so-secret weapon. While the rest of the nearly all-girl band – Adriano Cintra, Luiza Sa, Iracema Trevisan, Ana Rezende and Carolina Parra – showed slight signs of weariness, Lovefoxxx was the one who kept it together. She's a natural entertainer who sings in adorably accented English, dances like a drunk amateur stripper and runs rings around her band and the audience. She may be having the time of her life, but she also knows exactly what she's doing.

And, of course, there are the songs: perky, rainbow-bright and catchier than the common cold. Amazingly, the songs from CSS's eponymous debut album – the playground pop of "Alcohol", the bratty, dirty electro of "Alala", the cheeky disco-punk of "Let's Make Love and Listen to Death from Above" (which got the biggest cheer of the night) – still sounded as refreshing as they did in 2006, when it was the sound of the summer for a handful of in-the-know music fans. Back then, the album got to No 69 (yes, really) in the UK album chart. These days, they manage to fill the 2,000-capacity Astoria with every tribe of pop fan known to man, from glowstick-carrying teen moshers to business-card-carrying thirty-somethings and, standing in front of me, a man who looked like he was in his late sixties – and all of them singing along to the likes of "Music is My Hot Hot Sex" ("My music is where I would like you to touch!").

London is often named and shamed as the city with the most coolly indifferent gig goers in the world, but CSS were having it their way by bringing Brazil to the grim West End – at the end of the show, the venue was as hot and humid as any South American summer, and everyone was dancing like there was no tomorrow. You can bet that the same trick will be repeated around the world.