Time was that a film would give the moral majority angina if it even mentioned the word 'penis', let alone showed one. But the times, they are a-changing. In mainstream cinema, unsimulated sex is almost becoming old hat.

Recently, we've had 'legit' actors Kerry Fox and Mark Rylance living up to the title of Intimacy, Chloe Sevigny blowing more than her lines in The Brown Bunny and director Michael Winterbottom filming his leads going all the way in 9 Songs.

So, perhaps realising that their outrage generated more interest than any of these otherwise unremarkable films deserved, America's conservative right greeted the release of Shortbus with little more than an indignant harrumph.

Yet – thronging with transvestites, exhibitionists, voyeurs, gay sex, straight sex, group sex, solo sex, penetration, domination, ejaculation and masturbation – it's the most explicit of the lot.

The sticky curtain-raiser introduces Sofia (Lee) having vigorous sex with her husband, filmmaker James (Dawson) practising an awkward yet satisfying yoga move, and dominatrix Severin (Beamish) whipping a chap into a frenzy.

Emotionally, they're much less expressive. Referring to herself as a 'couples counsellor', Sofia is actually a sex therapist who has never having had an orgasm.

This she admits to James and his long-term boyfriend Jamie (PJ DeBoy) who she is mentoring through a rough patch. The boys introduce her to the wonders of Shortbus, a club for sexual and political liberals where anything goes.

(Most American children go to school on those long, yellow buses, but those with special needs – being fewer - travel on the short ones. Hence the club’s name.)

As James and Jamie form a ménage-a-trois with sensitive Ceth (that's "Seth"), Sofia finds herself warming to social butterfly Justin, and discovers that Severin actually has a thin skin under all that leather.

When it all comes down to it, Shortbus is a rather sweet film about fulfilment, love and belonging... wrapped in writhing bodies.

Unlike his self-regarding Hedwig And The Angry Inch, writer-director Mitchell injects fun into even the most salacious situations. "It's like the sixties... only with less hope," observes Justin of an orgy, just before a remote-controlled love egg creates havoc.

And you'll never hear The Star-Spangled Banner sung with so many bum notes.

Mitchell also delights in life's little ironies - a dominatrix soaking her aching feet; a lady from Suicide Watch dozing on the job - and emphasises the other-worldliness of the club by using an animated model of New York for most of the exteriors.

Come for a ride - it'd be prude not to.

Elliott Noble