In Lost in a Harem Abbott tells Costello "you wouldn't make it to first base with a girl like that."
The "Tree of Truth" scene in Pardon My Sarong where the penalty for telling a lie under the Tree of Truth is getting hit on the head with a coconut. Costello repeatedly tries to tell "farmer's daughter" jokes, with Abbott constantly interrupting him and telling him that these stories are inappropriate. When a girl asks him what the man wanted when he went to the farmhouse, Costello replies "He wanted a glass of milk", causing dozens of coconuts to fall on him.
The "You're 40, she's 10" routine. As Costello puts it, "You got me going around with a 10 year old girl, you've got a fine idea where I'm gonna end up!"
While in Algiers in Foreign Legion, Abbott warns Costello that it's illegal in this country to get familiar with women. Costello notices a woman with lots of kids and says "Boy, is that woman in the wrong country!"
That movie is full of Radar moments, especially when Costello drives a Jeep through a woman's bath.