It’s an old-fashioned horror movie about modern humans being possessed by ancient spirits, with plenty of nudity and over-the-top acting, as the good lord intended for horror films.
Troubled couples head to a transformative retreat in Finland, where they fall prey to a malevolent ancient goddess of love.
There are at least two Finns in the cast, but IMDb says that the film was actually lensed in Ontario.
My headline is a little misleading, because Zima did only teases, while everyone else in the cast got naked for real, including two old ladies. I put Zima’s name in the headline because she’s the most familiar performer.
There is even a scene where everyone got naked together …

… except Zima, whose place was taken by a body double who is at least 5 inches taller.

The Zima character is holding hands in that frame with Leonardo Nam, who is 5’10”, meaning that the woman in that group shot is more than 6′ tall. In contrast, Zima is 5’8″, and is clearly shorter than Lam when they stand together with both faces in the frame.
Zima did do a sex scene, but it was one of those deals where they used angles and elbows to hide her nipples. I don’t think there was ever a clear look her nipples.
But if you look closely, a few frames allowed a look at her mons, even though she again kept her breasts well concealed.
Here are the others in the cast:
Anne-Julie Proulx
Kimberly-Sue Murray
Kristina Tonteri-Young
Milla Puolakanaho
Sheila McCarthy
Gloria Slade
There was also a brief full frontal of the old ladies, Sheila and Gloria, but it was blurred.
Tracy Messenger is listed in the cast as a body double. I assume that must be for Zima, since everyone else did clear nudity.

Hmmm shame, Madeline’s got a great ass – not a fan of this recent lighting trend of so much backlit “natural” light it makes any nudity into a silhouette
I wonder if Zima had a bad experience in the past, she did great nudity in Californication
While that first season of Californication doesn’t seem so long ago, it has actually been 20 years since it was filmed. She was 20 then. She’s 40 now.
While she didn’t expose her butt in this film, she did wear some loose jogging shorts.
She was completely naked in Perry Mason 6 years ago. And that was basically her only scene in the entire show. Maybe she’s only willing to get naked if there was a bigger budget.