Lowbrow youthploitation comedy (10% at RT) featuring some future stars in their younger days. This trivia from IMDb tells you all you need to know about the film:
Originally in the singing penis scene, Michael C. Maronna’s own naked penis was used with a CGI mouth added in. After being screened for the MPAA, however, the filmmakers were told to put a sock on it (literally).
Mamie Van Doren was one of the blonde bombshells of the 1950s and early 60s, so the first thing you should notice in my headline is the disconnect between her name and the 2002 date. That’s not a typo. Mamie was 70-something when she did this nude scene. The clean-cut guy who looks like a younger version of Jason Schwartzman is, in fact, Schwartzman.
Just a couple of years earlier, Mamie showed off her stuff on a German show called “Liebe Suende”

Let’s leave the geriatric nudity behind. She did do a nude scene in her prime, in a 1964 film called Three Nuts in search of a Bolt
Film clips from Three Nuts can be found here
And you older guys will remember seeing Mamie in content like this:
Mamie is still alive, by the way, at 93.

She is very active on twitter where she used to post recent nudes but I think she stopped once she turned 90. Now all her posts have that adult content warning even if she hasn’t really posted NSFW recently.
Interesting tidbit, since her entire career is basically being the poor man’s Marilyn Monroe, some of those youthful nudes were shot by none other than Tom Kelley who famously shot the famous Marilyn nudes. If your a fan of his work or classic classic pinup nudes, I reccommend getting a copy of his book.
The 2000s were a helluva drug – crazy Mamie never worked with Russ Meyer
In terms of the oldest actresses who did nudity on film, I think Emmanuelle Riva and Jessica Tandy are tied at 85. Emmanuelle surprisingly has rather large and firm breasts as well.
The only Bridget Fonda nude scene I’d skip is the one where she skinny-dips with Tandy