In the episode "Bye, Bye Birdie", Filburt's bird, Turdy, rips off Bev Bighead's bra, having Bev to reply, "Oh! You naughty bird!"
One episode title is called "Carnival Knowledge".
In one episode, Heffer throws a nudist party at Rocko's party (Rocko seems disapproved about it). In the same episode, when Ed Bighead happens to be spying on them, Bev happens to take a perverted interest into it, and, for some reason, throws one herself at the end of the episode.
In "Carnival Knowledge", the slug, who is running the carnival, is seen reading a "Playslug" magazine at one point.
In one episode (the banned one), if you look closely at the documentary that Rocko and Bev are watching, you can see a female frog with breasts and nipples in plain sight.
One recurring restaurant is named "Chokey Chicken" (the name was changed in season 4).
In "Schnit-Heads", there's a scene where Heffer has a hot dog in his pocket. Rocko notices, and asks him, "Do you have a sausage in your pocket?"
In "Who Gives a Buck?", when Rocko and Heffer were riding on a train through the store, the salesman tells them that they must sit "doggy style".
In "From Here to Maternity", one scene heavily implies that Heffer and Dr. Hutchison had an affair (Dr. Hutchison's third son looks like Heffer with Filburt's glasses).
Tons of sexual innuendo throughout the show, but never really explained clearly.
One character started working for a phone-sex company in a short sequence.
In one incident, Rocko picks something that resembles a berry on something that resembles a bush. The bush turns out to be a furry animal and the berries turns out to be his testicles, as seen when the animal stands up and grabs his crotch in pain.
One episode had a character trying to seduce another. Later, the girls husband returned home, only to see another male character in his underwear with money in his hands and believed she got payed for sex.