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 The Chief's Daughter 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.