A lie of a 4-year-old

My son will be 5 in three months.  While anyone that knows him would say he's 4 going on 20 ... he is still a four-year-old.  A loving, sweet, still-mispronounces-many-many-words, just learning to ride his bike without training wheels, still sucks his thumb, four-year-old little boy.

But lately ... we've been catching him in lies.  I say "lies" but it's one lie ... over and over.

Cash knows how to wipe his butt.  We taught him as soon as he started pooping in the potty at three.  So for nearly 2 years now, he's been wiping his own ass.  Until recently.  When we noticed that not until has he not been flushing after he pooped .... but there was no toilet paper in there. Not to mention the stains in his undies.

He said he "just forgot to".  So he'd been warned that if he doesn't start wiping his hiney ... he would have to stay in his room for the rest of the day. And that Mommy and Daddy WILL know if he's not wiping.

So a week ago, when he came out of the bathroom after a decent amount of time in there, Cale asked him if he wiped.  Cash told him he never even went poop, he was just in there peeing a long time.  Cash was smart in flushing the toilet so that we didn't know if he wiped or not.  But Cale could smell that Cash had just lied to him.  Now if the kid wasn't such a newbie at lying, he could've easily covered his ass (literally) and said: "Yes Daddy, I wiped" and Cale never would have known because Cash actually flushed the toilet for once.
But instead, he set himself up and didn't think that Daddy would get up and do the smell test.  [Repeat again a couple days later - the exact same thing]

While my heart breaks {and scares me to death} because it seems like "it's starting soooo young" ... it's still a teeny tiny little lie ... from a four-year-old boy who still needs a nightlight on and is too scared to walk down the dark hallway ... over wiping and pooping.