CINEMANIA: Guess the movie title

Little Johnny sees his Daddy's car passing the playground and going into the woods. Curious, he follows the car and sees Daddy and Aunt Jane kissing.
Johnny finds this so exciting and can barely contain himself as he runs home and starts to tell his mother excitedly.
"MOMMY, MOMMY, I WAS AT THE PLAYGROUND AND DADDY AND..."
Mommy tells him to slow down, but that she wants to hear the story.
So Johnny tells her. "I was at the playground and I saw Daddy's car go into the woods with Aunt Jane. I went to look and Daddy was giving Aunt Jane a big kiss, then he helped her take off her shirt, then Aunt Jane helped Daddy take his pants off, then Aunt Jane laid down on the seat, then Daddy..."
At this point, Mommy cut him off and said, "Johnny, this is such an interesting story, suppose you save the rest of it for supper time. I want to see the look on Daddy's face when you tell it tonight."
At the dinner table, Mommy asks Johnny to tell his story. He describes the car into the woods, the undressing, laying down on the seat, and, "then Daddy and Aunt Jane did that same thing Mommy and Uncle Jeff used to do when Daddy was in the Army."