The problem with anhydrous (100% water free) ethanol is that it desperately wants water. The OH group rips water out of its surroundings like a chainsaw in a furniture store. It's unpleasant.
When you drink anhydrous ethanol, that water gets ripped out of you. It pulls it directly from the cells of your cheeks, tongue, esophagus ... whatever it touches until it gets diluted to ~95%. This hurts more than straight-from-the-350 degree oven pizza.
If you consumed this alcohol as a vapor the pain would be excruciating, and might cause chemical pneumonia.
If you inject it, there will be significant cell death in the area of the injection site.
If you are planning on getting sloshed from your laboratory stash, here are some tips:
- Make sure it is Ethanol. Other alcohols can be fatal.
- Make sure it has not been Denatured. Denaturing is mixing with other substances to make it undrinkable.
- Make sure your lab is moron free, and no-one returned their "extra" material back to the shelf container.
- Add at least 10% water. (50% Coke or 50% orange juice would taste better.)
- Don't drive or operate heavy machinery.
- Don't give yourself alcohol poisoning. An ounce or two will be more than enough to completely slosh a person not used to drinking. A 6 pack of 12 ounce cans of 5% beer contains 3.6 ounces of alcohol. 90% ethanol packs this same punch into just 4 ounces, just over two shots.
I, personally, wouldn't drink the stuff from the lab. It's fairly trivial to brew and distill alcohol. That would be safer and educational too. There are lots of websites that describe brewing alcohol. If you need a way to distill it, here is a copy of the
Guidebook to Constructing Inexpensive Science Equipment, Volume two - Chemistry.
... and here is an example of what "trivial to brew" means
From Caveman to Chemist: Mead
Yes, bread yeast will work. Don't sell it or share it; that'll ruin your life. There are laws enforced by very unfriendly people on this topic.