In the infamous "Sploosh" episode, Brittany's character at one point asks Jeanette (as the mermaid), "Are mermen sexier than human men?"
Even better from "Simon Seville, Superstar", Simon (an eight-year-old boy chipmunk) is asked how he feels about being a SEX SYMBOL! He is unsure how to answer that directly, but suggests that his glasses may have sex appeal.
In "Cinderella? Cinderella!", where Brittany dreams herself in the role of Cinderella, a scene of her forced to do various chores has her giving baths to her sisters. Both Jeanette and Eleanor's expies in the dream are shown sitting in small bathtubs, uncovered from the waist up, with small dots drawn on. Admittedly, such a thing back in the 80s was probably no big deal unlike today, but come on, what the hell?
"Dreamlighting", which parodied the show Moonlighting, has what appears to be a distraught Alvin suffering a hangover. Then we see that he's just been drinking root beer and he's had far too much.
In general there seem to be a lot of Panty Shots (from the Chipettes and other young girls) for no reason, although that may be an attempt at realism, as some of their skirts are quite short. Still...
Depending on how you interpret it, in an early episode of the 80s series, Alvin runs for school president, and at one point, his campaign slogan is: "Don't be a donkey, vote for Alvin!"
There was one episode when one of The Chipmunks teacher was generous enough to give
Alvin sees a psychiatrist in the episode "Alvin and the Analyst", who supposedly is a caricature/parody of a real-life sex therapist; granted, Alvin wasn't see the shrink for those kinds of problems, but still parodying a sex therapist on a kids' show?
The two main villains are seen smoking or at least holding cigars throughout the film.
While The Chipmunks and Chipettes struggle with controlling their balloons, Klaus can be heard muttering, "Gott it himmel!", which is German for, "God in Heaven!", of which can be interpreted as a swear against God, which is usually unheard of in children's entertainment.
with his friend Lalu so he can concentrate writing a song over the weekend. That means the six have to stay overnight and all the Chipmunks/Chipettes share the same bed with Lalu. Picture a babysitter sleeping with your kids...
There was a stripper reference in the second live action CGI movie, however, since they didn't say "stripper" or "prostitution" outright, most of the kids in the audience won't get it, which is what makes this a Getting Crap Past the Radar...or past the kids, anyways:
Alvin: It's Aunt Jackie. She's making us a zesty five-course meal. Dave: Really? Well, can I talk to her? Theodore: She's practicing her pole dancing. (Alvin and Simon look at each other) Dave:Pole dancing?
Not quite past the kids. In this day and age, it wouldn't be all that uncommon for a nine year old to know that pole-dancing is tied to a....certain profession.