Well, can't say Boog and Lenny don't have a point.
In "Chicken Pox", Kyle has been turned into an actual chicken due to... well... chicken pox. He yells at the eponymous duo to "shut the *CLUCK* up!"
After Kyle asks Fanboy and Chum Chum to leave because the situation is embarrassing for him, Fanboy replies "You shouldn't be embarrassed, Kyle. You have very plump thighs" and a whistle is heard in the background, although this is more of a reference to him being a chicken.
After they make those jokes, we get
Fanboy: Oh, oh, I got one. An EGG's gonna come out of your BUTT.
An exasperated Lenny once said "Ah... goh... dah......it."
In "Wizboy" Kyle says, "Like I give an ELF!"
In "Chimp Chomp Chumps", Fanboy and Chum Chum, having the power to manipulate Boog (they have one extra ticket for a movie he wants to see), make him do various, unpleasant things. Probably the most risque instance is when they force him to wear a maid outfit.
Fanboy comments that, "Chimpin' ain't easy," to the ticket seller (who is, in actuality, Lenny) at the Chimp Chomp movie premiere.
A more subtle instance of this occurs when Janitor Poopatine scans the mop's "corsage" in "Moppy Dearest".
In this episode, Lenny tries to convince Fanboy and Chum Chum to hand over Cuppy by saying the Frosty Mart is having a "cup exchange program". When he asks who wants to trade, Mr. Mufflin appears and throws an athletic supporter in Boog's face.
When Chum Chum returns to the Fanlair at late at night in "Night Morning", he hiccups with a mischievous look on his face.
Literally crap past the radar: the last line of "Precious Pig", in which Chum Chum says, "I think Precious just made brown belt."
In "Berry Sick", Barry the Ice Monster wakes up and says, "I just had a fever dream that I was licked all over..." Granted, it's because he tastes like Frosty Freezy Freeze, but still. Later in the episode, Barry comes out of their bathroom and says, "I don't know why you need another specimen..." Fanboy and Chum Chum were drinking his crap.
In "Dollar Day", the Frosty Freezy Freeze machine splurts a drop of the drink in Fanboy's eye, to which he replies "Oh, heh heh... feeling playful today?".
In "Monster in the Mist", Fanboy and Chum Chum make a Knife Outline of Boog, who doesn't react until there's a fork flying towards his crotch - that's when he screams out in horror.
Boog: "What, are you nuts?!"
"Bite me!" (Quick and discreet in "Fanboyfriend.")
When Boog brings the Chimp Chomp machine back to his apartment: "Don't worry, I believe in surge protection."
In "No Toy Story" Fanboy asks what Chum Chum is doing in the dark, he responds "...Pillow talk?"
In "Present Not Accounted For".
Chum Chum sticks a pin in Fanboy's butt in an attempt to play Pin the Tail on the Donkey, he says: "Did I pin the tail on the donkey?" And Fanboy guiltily replies: "In a manner of speaking..."
Janitor Poopatine approaches Fanboy shadily in the hallway, "Looking for a little action.... figure?"
In "Kids In The Hall", Kyle is "speeding" down the hallway on his broomstick when he is "pulled over" by fanboy and Chum Chum dressed as cops. Fanboy leans close to Kyle, sniffs, then asks if he's had any potions or elixers today, to which Kyle responds: "No! Well.. Maybe one at breakfast... But that was hours ago!"
In "Fanbidexterous" Fanboy begins using his left hand for things. At one point he remarks "It's so weird! It feels like a stranger!"
In "Back From the Future", Lenny climbs into a walking, talking video game machine. From its rear. The look on said machine's face is priceless.