WHAT is that SMELL?!?!

Last night, Wayne and I went into Jack's room to help him pick up before bed. 

(Yes, he's almost 5 and should do it on his own but we're slacker parents and haven't cracked down yet.  Don't be so judgy.) 

Anyway - walking in, we smelled a distinctive "potty" odor.  Assuming the dog had pooped, we picked up everything and couldn't find the source of the smell.  By the time I was done spraying Vanilla Lysol, you couldn't smell anything malodorous.  We assumed it must have been a passing whiff of little boy fart or something. 

This afternoon, the smell was back with a vengeance.  I could NOT find the source.  On the way home from dinner, Wayne and I were discussing it...

Me: When we get home, we need to go through his room and try to find the source. 
Wayne: Ugh.  What do you think it is?
Me: I have no idea.  Maybe we should just change his sheets?
Jack: Oh.  It's probably because I peed in the trash can.
Both parents: WHAT?! YOU DID WHAT?!  WHEN?!
Jack: I don't know.  I was on top of my bed [a loft bed] and peed down into the trash can.  It looked so cool.
[Wayne and I attempt to hide our laughter - because while thoroughly disgusting and inappropriate, the image of him doing it is kind of funny and it's HIlarious that he thinks it's "cool."]
Me: Jack - you cannot pee into the trash can.  That is disgusting.  You only pee in the toilet.
Wayne: [something similar to what I said]
... and so on...

We get home and it is, in fact, the peed in trash can from MONDAY that smells so bad.  It didn't help matters that he'd apparently had a little accident and put undies with a little poop on them in the trash.  FAAAANtastic.  Really.  Parenting.  Funny, yet gross.