I had to suitcase it to get it past the screws!
Funny, I used to use to 80s toy Falcon at a hiding spot for well…anything. The rest of my SW toy collection helped conceal anything else I might need.
Also I discovered that if I unscrewed the plate on my bedroom light switch, I could stash small items between the walls.
Our house was built to spec, so my parents had a laundry chute installed that ran straight down from inside an undersink cabinet in the 2nd floor bathroom down to the basement. The opening was crudely finished, and permitted access to the area under the floor with a little arm stretching.
I also had a collection of 40 or 50 mugs/beer steins/glasses from various countries on a shelf in my room; way too many to inspect on a regular basis.
The attic entrance was in my bedroom closet, so this got repeated use as well. I typically hid cigs under the insulation, just in case my Dad ever needed to go up there. I would stand on the shelf in the closet with my head in the attic and smoke, and could be down without notice upon hearing my Mom entering the house downstairs. This was considerably more inconspicuous than the closing of a bathroom window. 
It’s a testament to my parents’ sleuthing that I was caught as often as I was!
I used to stuff my Flinstone’s chewable vitamins down the heat register. One day Mother cleaned only to find a couple inches of vitamins.
I don’t remember getting in trouble (I’m sure I did), but she gets the last laugh anyway, I never made it past 5’ tall. Should have taken those freakin’ vitamins.
Hmmm, I read that, but I’m not sure it explains why there’s a draft entering the house through the chimney on humid days.
I liked to hide things out in the open like the Purloined Letter, e.g. something inside a book that was haphazardly thrown on the side in full view.
The inside pockets of heavy winter jackets, in hiking boots, cleats, or any other article of clothing that does not get used all that much were good hiding places. The front cover of my big ol’ stereo speakers were removable- plenty or room in there. Battery compartment in any battery operated thing like a boombox was good for hiding small things.
I used the floor under the bottom of the lowest drawer of the desk, until our cat decided to take advantage of the open drawer to move her kittens in there. Contraband doesn’t mew, which really helps it stay hidden.
After that I moved to the space above the door to the closet. Walk in, turn around, reach way up, and hide stuff. The cat was nice enough not to leave anything there.
Or steal my stuff.
Hiding stuff in my house wasn’t much of an option. Too many spying siblings. Had plenty of forest around to hide stuff.
I’ve always hated most vegetables – I’m 31, and I still do. When I was 12 or 13, I started slipping them into my pockets when my parents weren’t looking, and then flushing them down the toilet at my leisure. I haven’t eaten a green bean since.
I didn’t have a whole lot of contraband, but I grew up in an old house with a big, unfinished basement and a big, unfinished attic. Both were pretty cluttered to boot. No shortage of hiding places.
When I was young, my desk was next to the dinner table. My sister had a habit of hiding her egg yolks in my drawers.
I made a big, nifty-looking dragon out of legos that I kept because I was so proud of it. (It was awesome. I wish I had a picture of it.) It was hollow on the inside, and it didn’t take long for me to figure out I could hide stuff in it. I also used the space under the bottom dresser drawer that some people have mentioned.
When my husband and I were house hunting a few years ago, we found someone’s stash. The hand rail on the stairs to the attic was hollow. At the top end was a wooden plug. I was fiddling with the end of the railing and accidentally popped out the plug. Inside the hollow rail was a baggie of weed and a pipe.
My room had ceiling tiles, so I hid my porn up there.
When I was underage I always wanted cold beer, but my dad didn’t drink and wouldn’t allow it in the house.
So when I was able to get beer I would buy a 12 pack of soda no-one else drank and lay it on the 4 can side, open the little “grab a can” pouch to display the one can, than stuff the rest full of booze.
I still can’t believe I never got busted