Moldy Peaches, Roadhouse, Manchester<br></br>Primal Scream, Shepherds Bush Empire, London

Get yer rocks off, kiddywinks

Did you know that they're making Hello Kitty vibrators now? You can buy them over the internet. It's surely the most Moldy Peaches object I can think of. (Bear with me here, I promise I'll explain.) There's always something worrying about infantilism in grown-ups. Don't get me wrong, what consenting adults get up to behind their bedroom doors is no one's business but their own, but it's nevertheless difficult to remain un-creeped by colour supplement articles about adult babies. Even in its milder forms, this refusal to acknowledge the onset of maturity – telltale signs: collecting Sanrio and Barbie ephemera, wearing cutesy hairslides – is only becoming in those who were genuine infants fairly recently. Adam Green (20) and Kimya Dawson (28) can still just about get away with it.

Militant kiddie-rockers The Moldy Peaches habitually take to the stage looking like something out of the Play School toy cupboard. Green, who used to wear a green felt Robin Hood outfit, tonight wears a tall Guy Fawkes/Wicked Witch hat. Dawson, in the past, has dressed as a kitten, a lioness and a bunny. Tonight her untamed blue afro is hidden by a huge Bungle-from-Rainbow bear's head. In a venue where air conditioning is still regarded as some weird new magic, for this she commands my utmost respect.

They're backed by one princess and one Bonnie Parker (both male), plus one unicorn in the form of Jack Dishel, whose squealing Mick Ronson-style solos chafe incongruously against Adam and Kimya's lower-than-lo-fi strumming.

The Moldies emerged from New York's anti-folk scene, the movement whose raison d'être was, as much as anything else, to spite the reverential traditionalism coffee-house scene, and cause Dylan and Baez to spin in their zimmer frames. In a way, though, there's something small-p political about them.

On "Nothing Came Out", a beautifully poignant description of a girlish crush in the world of grown-up dating, Kimya sings: "And besides, you're probably holding hands with some skinny pretty girl who likes to talk about bands/I just want to ride bikes with you and stay up late and watch cartoons..." The Moldies are all about the friction between childhood dreams and adult realities. One minute they're digging Josie and the Pussycats and Scooby-Doo, or reminiscing about a pubescent fixation on the members of Duran Duran, the next they're yelling about "sucking dick for ecstasy". Which is where the vibrator comparison comes in.

Of course, if you put any such analysis to Green and Dawson, they'd laugh themselves silly, and when you hear their absurdist anthem "Who's Got The Crack" ("I am a goat... in a moat... with a boat... who's got the crack?"), you concede they have a point. The bottom line is that right now, Moldy Peaches are possibly the most fun you can have standing up.

They are also one of two bands who have had their set lists altered since the unfortunate conjunction of three aeroplanes and three famous buildings towards the end of last summer. "NYC's Like a Graveyard", an uncharacteristically rockin' Stooges soundalike, was intended as a parochial gripe against the culturally moribund state of their Manhattan surroundings, but the title and the eerily prescient lyrics ("All the yuppies getting buried... New York City is a cemetery") mean they've had to ditch it indefinitely.

The other band in this position is Primal Scream, whose 2001 comeback single was due to be called "Bomb the Pentagon". In retrospect, it's difficult to decide what was more embarrassing: Bobby Gillespie's belated and rudimentary discovery of global politics at the age of 39, or his squirming climbdown post-11 September (when they said "bomb the Pentagon", they didn't literally mean "bomb the Pentagon" you see, blah blah).

I saw Bobby Gillespie cycling through Canonbury Square the other day. It wasn't a 900 quid mountain bike, such as one might expect a wealthy rock star to own, but the sort of vintage boneshaker that one of John Major's imagined old maids might ride to church. It was a vignette that summed him up: for someone so clearly obsessed with carefully-studied cool, he's incapable of exuding any. Which, paradoxically, makes him cooler still in the eyes of many. This is why, when he dances like a drunk morris dancer at a wedding reception and claps his hands like a paralysed sea lion, or shouts "Oh yeah baybeh come awn alraaht!" by way of a "Hello", Shepherds Bush screams its affectionate approval.

The crux of the argument is whether Gillespie is an idiot savant, or whether the "savant" bit isn't necessary. There's plenty of evidence both ways. My friend thinks Gillespie is "rubbish, but he's been involved in two of the greatest albums of all time." Those two albums are The Jesus And Mary Chain's Psychocandy, on which Gillespie played drums, and his own Screamadelica, which married Sixties psych-rock, Sun Ra avant-jazz and gospel to the loose dance grooves of the early Nineties.

Sadly, for 2,000 people who have paid through the nose, there's no Screamadelica tonight. With only a cursory "Rocks" representing the PS back catalogue (no "Loaded", "Come Together" or "Movin' On Up"), most of tonight's show is lifted from forthcoming album Evil Heat and its predecessor, XTRMNTR. One new track, "Autobahn 66", says all you need to know about where Primal Scream are at in 2002: American rock'n'roll and German electronics.

"Bomb the Pentagon" sneaks into the set, now meekly titled "Rise". So does the Primals' other call-to-arms: "Kill All Hippies" remains a strangely hypocritical euthanasia plea (some of us remember the Sonic Flower Groove album, you know). "Swastika Eyes" is tonight's finest moment, sounding like "Heart Of Glass" reworked by Motörhead. Silly old savant he may be, but every now and then, even Bobby Gillespie can blunder into moments of idiot inspiration.

s.price@independent.co.uk