As predicted with this thread - virtually all of those are interesting alternative uses rather than better uses than the intended function; mixed in with a few cases like Viagra where the intended use changed.
As long as we’re talking about Bic, the top to a Round Stix pen is perfect for scratchin’ yer ear. You can hit that one spot and make your legs shake!
I’m pretty flexible, but I don’t quite get your meaning.
Dan
These things
I have never tried to use conditioner as shaving cream. But I guess it holds water…
I did not know this, but QIROUS^ suggests that only the American formula of Preparation H changed and Canada still has the original. Kind of like Mexican Coke. You folks need any and a friendly SDMB Canuck will send you some for a modest handling fee. 
^ Quick internet Research Of Unverified Sources
I spent most of a summer spray painting bomber beds (road salt hopper/spreaders that go on the back of trucks) and snow plows. I got covered in over spray every day. Regular soaps and cleaners wouldn’t touch it.
I took a co-worker’s advice and tried baby oil on it. The oil took the paint right off, and regular soap took off the oil.
In fact, this is news I can use. Thanks!
The fact QIROUS can be pronounced about like “curious” is one of the most delicious wordly discoveries of the day, if not year to date. Or did you do that on purpose just for us?
Made it up on the spot. Didn’t think about how one might pronounce it - but it works. Thanks.
Q-Tips for sure, I mean, really.
Bic lighters are great for fire but for the life of me I can’t open a bottle with one.
WD-40 is interesting too. Water Displacement 40. Was originally used for missiles as an anti corrosive. Ok. Now it’s in just about every house a quick lubricant for small parts. Locks, hinges and stuff.
Oh, the glue on sticky notes was not originally designed to create a ‘sticky’ note. An entire industry evolved out of that.
Disposable douche makes an excellent skunk odor remover. Seeing that douching is mildly harmful, I’d say it’s a better use.
Wait, is there a permanent kind?
This may be a very German thing. Most Germans can open a beer bottle witth one (me too!), but no Spaniard I know can. Russians, OTH, open beer bottles with their teeth, I have seen that. But I am sure that is not a better use than their intended function, so I’ll stop it here.
Yeah, that crossed my mind too, but that’s what it says on the box. I think it’s the bag that’s disposable.
As I remember, an ordinary douche was a rubber bag and hose and wand setup. You’d fill the bag and hang it up high, often on the shower head, and use it in the tub.
But I haven’t seen one of those in a long time.
It’s “portable tampons” that have me stumped.
Yeah, almost all of my friends can do it (and they’re not all alcoholics…). Once you have the technique down, it’s the easiest thing, and I bet I can open a bottle with a lighter faster than anyone with a regular bottle opener. The bonus is that once you can open a bottle with a lighter, you can open it with almost any other kind of tool, like a screwdriver, a hammer or even another (unopened) bottle. But some people never learn it. I tried to teach the skill to a friend, and instead of opening bottles, she managed to open one or two lighters with the bottle.
Must. Not. Make. Political. Jabs. In. IMHO.
I can open a bottle with pretty much anything but a Bic Lighter. Last time was the Airport hotel in DIA. the latch for the bolt on the door worked just fine. Or give me any sturdy piece of steel. Or even a counter top that is sturdy that I don’t want to mar. All you have to do is push, or bang it with the palm of your hand.
Bic Lighter, not happening. 
I stopped worrying about it since there are tools everywhere. Just have to know how to use them.