Here's the scenario: You're going at it. All of a sudden, mid-thrust or mid-moan (for extra embarrassment), you hear a little voice. "Mommy, what are you and daddy doing?"
You have three choices: Run and hide, lie, or offer an explanation on the fly ("Daddy and I just wresting, honey!"). Then stress-out for months afterward about whether your child will be emotionally scarred for life.
But, there's a better way to do it (not talking sex tips here ... focus ... this is about keeping your kid from telling his whole preschool daddy's penis hurt you last night). You can get caught having sex and survive. It is possible.