I've done this shit.
I had about half a fifth left and had nothing to do on a thursday night and figured what the fuck, so I got some vaseline and lubed my butthole up real good, and drenched a tampon in some Russe and shoved it up there, there was an initial burning that really sucked, kinda like having fire whole after some hot wings or mexican food and having a lot of diarrhea. Anyway, it only took about 30 seconds before I felt the buzz, I kept it up there for about 5 minutes until it "felt" fairly dry, and then wound up and did another one, this one burned less, but yea again 30 seconds went by and I immediately felt another kick, and I could feel my self getting drunker. I then waited five more minutes and yanked that shit outta there.
I wouldnt say Id do it again but its definitely something worth trying.