If you can find a place outside for temporary storage, it's a lot easier. Now, granted, a diaper you've gone #2 in is going to smell so bad that, even bagged and outside, they'll still be able to smell it within 10 feet. But if you've only done #1 it's a lot easier to hide it. Unless you REALLY want to, I strongly recommend against doing #2 in your diapers. It's dirty, it's smelly, it's hard to clean up, and it's very hard to hide the used diapers.
For a diaper I've done #1 in, I'll stick it in a trash bag, knot the bag as far down as I can (the less air space the diaper has, the less it will "ferment"), and then hide it outside under a pile of old junk at the side of the house. Then, on trash day or the day before, I will put it in the trash at least 2 layers down. If I cannot get it out on trash day itself, though, I will wait a week. A week in the open air lets it quit smelling, so there won't be any smell when I finally DO put it in the trash.
For other people, there's dumpsters, gas station trashcans, and such. Any public trashcan you an drop it in.