It's not so much that you're guaranteed to die as you will be at much greater risk if you make any sort of mistake.
You don't have to experiment, you can do the math. LD50 while not established on humans (per the datasheet I looked at) appears to be about 6500mg/Kg, which is about 83cc/Kg for 70%. Of course this is oral, and rectal administration would lead to peak blood concentrations much earlier and higher (as the liver would have less time to metabolize the alcohol before it was all in the bloodstream). I'm sure that you can find rectal vs oral absorption figures somewhere if you want to compute this.
As for "hurting"/"burning" one of the great dangers to any sort of anal/rectal thing is that the colon can't sense pain generally, so you wouldn't have any warning until the damage was done. Likewise the stomach stores things that come in via the mouth, so you can vomit stuff out if there's a noticeable toxin (and you have warning), which can potentially save your life. The rectum doesn't have this advantage, and while things can come out (and it would be much more embarrassing than a mere episode of vomiting) this isn't assured.
And one last bit of amusement, from the Ethyl Alcohol 70% MSDS:
"Odor: Mild, rather pleasant, like wine or whiskey"
You don't have to experiment, you can do the math. LD50 while not established on humans (per the datasheet I looked at) appears to be about 6500mg/Kg, which is about 83cc/Kg for 70%. Of course this is oral, and rectal administration would lead to peak blood concentrations much earlier and higher (as the liver would have less time to metabolize the alcohol before it was all in the bloodstream). I'm sure that you can find rectal vs oral absorption figures somewhere if you want to compute this.
As for "hurting"/"burning" one of the great dangers to any sort of anal/rectal thing is that the colon can't sense pain generally, so you wouldn't have any warning until the damage was done. Likewise the stomach stores things that come in via the mouth, so you can vomit stuff out if there's a noticeable toxin (and you have warning), which can potentially save your life. The rectum doesn't have this advantage, and while things can come out (and it would be much more embarrassing than a mere episode of vomiting) this isn't assured.
And one last bit of amusement, from the Ethyl Alcohol 70% MSDS:
"Odor: Mild, rather pleasant, like wine or whiskey"