"We need God."

These are the amusing words of caution that open up "Wetlands," playfully presented on screen, along with the rest of the quote’s source material: a letter to the editor vehemently rallying against the film about to begin and the Charlotte Roche book it’s based on. Starting your movie with a quote? Typical. Using a quote decrying the movie’s creation? Less so.

That concerned citizen might be pleased to know to know that God seemed very much present in my particular screening, as people were muttering and exclaiming "Jesus!" for much of the running time. Then again, it usually came surrounded by shocked, entertained giggles, so maybe not.  

If the movie's opening moment desperately pleads against its existence, the ensuing 109 minutes of youthfully exuberant gross-out comedy – currently showing at the Milwaukee Film Festival with a final showing Monday night at the Times Cinema at 10 p.m. – couldn’t be a more enthusiastic endorsement for it.

Director David Wnendt’s coming-of-age adaptation is an blissfully obscene berzerker, a gleeful – as well as gag-full – carnival of crazed carnality. The repulsively unwatchable has rarely ever been so compellingly watchable. 

In a brave and bright star-making turn, Carla Juri stars as Helen, a young German teen with a hunger with all things related to her body, sex and all the messy, drippy, oozing fluids flowing in between. Pretty much every bodily substance gets at least an extended cameo in "Wetlands," all of them serving as objects of fascination for Helen.

Her adventures into the swampiest parts of herself – as well as the swampiest parts of the local restrooms – come to a screeching halt when she cuts herself hastily shaving her bum, sending her to the hospital with a nice anal fissure to go along with her handsome collection of hemorrhoids. Have I mentioned "Wetlands" is nasty? Because it’s nasty.

While recuperating, Helen makes flirty trouble for her kindly nurse Robin (Christoph Letkowski) and shares debauched stories – namely about a disgraced delivery pizza that cannot be unseen. Her main mission, however, is bringing together her loveless parents. Things aren’t progressing well though; her uncaring father (Axel Milberg) has happily moved onto other, younger and bubblier women, while her mother (Meret Becker) is Helen’s polar opposite: a depressed, chilly clean freak.

In a world where "Sex Tape" and other raunchy Hollywood comedies can be squeamishly embarrassed by simply the idea of sex, there’s something refreshingly invigorating about "Wetlands," a movie that goes after taboos with such a giddy fervor.

Starting with its clever first shot and a title sequence pulled out of a sci-fi prehistoric peyote nightmare, Wnendt shoots the film forward like a coked-up lightning bolt. He races through the imaginatively irreverent jokes and sequences with the aid of ecstatic rapid-fire edits, vibrant colors and a driving, bounding soundtrack. It’s got a furious creative energy all too befitting of a picture about youthful rebellion and discovery.

He’s blessed with an equally audaciously eager lead performance from Juri, who dives into the character of Helen with no reservations. She’s gross alright, but she’s also distinctly human: charming, punky and a bright playful beam of charisma on screen. She fearlessly makes the character not just a freakshow to gawp at, but a person who comes alive in all of her tenacity, tenderness and unsanitary insanity. Between Wnendt and Juri, their joint lust for life and liberty (and lust) is contagious – even when you’re cringing.

"Wetlands" gets a lot of entertainment miles out of its often shocking grossness. Even with all the different squishy organs and parts vying for attention, however, it’s an unexpected one that comes through the most: its earnest, vigorously beating heart.

The movie never becomes simply an amusing shockfest to be endured. There’s always a humanity mixed in with the potential for hurling. With Wnendt and especially Juri behind the wheel, it’s a surprisingly sweet sincere story about a girl growing up with some, er, unusual habits and interests, as well as some buried emotional baggage. Helen may be willing and eager to find the dirtiest toilet in the city, but as it turns out, there are some things in her memory she won’t touch.

Unfortunately, "Wetlands" isn’t quite able to maintain its fireball of energy all the way to the end. The back end, while still quite good, doesn’t quite have the same charge, and the story tends to be on the unfocused side of things, drifting around a bit. Still, few movies – especially from the well-trodden modern coming-of-age genre – feel as electric and spirited as Wnendt’s film at its peak. 

Plus, it pulls off what doctors, dieticians and health instructors once thought was impossible: get people to think twice about ordering a pizza.  

"Wetlands": ***