I've found something that, for me, is superior to the medicine spoon technique. I tried the medicine spoon thing, but found that the hard plastic cup thing was, um, pretty uncomfortable. But more importantly, I had a heckuva time directing a stream out of the other end. The hole you drill has to be perfectly straight and a clean cut for it to work; if you just cut the entire end off, liquid doesn't exit like a stream... more like a mini-waterfall. Not realistic at all, IMO.
Instead, try getting a medicine dropper (the one I used was from Wal-Mart & came packaged with a medicine spoon; look in the pharmacy section). The medicine dropper has a vinyl bulb at the end that is *very* easy to cut with a utility knife or an X-acto blade. Cut the vinyl bulb in a similar shape to the spoon end of the medicine spoon. The bulb and the spoon are actually about the same size. Don't get one of those *really* tiny medicine droppers; the dropper I'm talking about is about around 5 inches long. The best thing about it is the end where liquid exits: it is a very clean-cut hole that yields an easy-to-direct stream that doesn't dribble all over the place. Also has a nice arc to it. I've never had it back up on me. Oh, and the vinyl end is a bit more comfortable & gets a better seal, I think.
I'll put up pictures of one I made as soon as I get back to my apartment this weekend.