Yes, it may come as a surprise to many who read this, but I drank in college (although I was ahead of the curve on the drinking age and it was legal when I was 18 - of course I had my first beer at age 16). I have even imbibed to excess at times (I still don't care for certain mixed drinks I once liked). I have never, however, even in my most depraved younger days, ever, thought of shoving a rubber hose up my ass (or asking a male friend to shove a rubber hose up my ass) to obtain my alcohol rectally.
Turns out the fine young men at the University of Tennessee's Pi Kappa Alpha fraternity have different views on such activities (Tennesse Fraternity Suspended After Alcohol Enemas). Butt chugging (I understand that's the street term for this activity) is apparently popular in some circles (circles I don't want to join). The UT boys used cheap box wine since you can take the bag out and hang it as an enema bag. Probably stole the rubber tubing from their chem lab.
Why? Perfectly sensible question. Well, first, because they're fucking morons but, secondly, because your rectum will absorb the alcohol direclty into your bloodstream faster and more efficiently than your stomach will. Want a near-fatal 0.40 BAC with just a few ounces of booze in a few minutes? This is your method. (By the way, in doing the "research" for this post, I learned that women will sometimes insert alcohol-soaked tampons into their you-know-what for the same reason - Isn't the Internet a wonderful tool for knowledge?).
Call me old fashioned, but I much prefer just sitting around with my friends, asshole not exposed, and ingesting my alcohol orally. When doing shots, I don't think I'll ever use the phrase "bottoms up!" again without disturbing images and young men and enemas popping unbidden into my head. Cheers!