My hydrometer came in a rather flimsy plastic case that is perfect for measuring. What did yours come in? Did you throw out the case?
I have a "thief", but it's only 6 or 8 inches long, so unless the top level of beer is near the top of a 5-gallon carboy, it doesn't do the job. So, what I do is orally siphon...don't worry, nothing that my mouth touches ever gets near the beer in the carboy. I sanitize the hell out of my racking cane and tube. I stick the cane end into the beer, suck on it until the tube is filled, then hold my tongue over it while I pull the cane back out and release it into a measuring cup. Depending on the length of the tube, this is typically enough for me to get a reading from. It's not the best method in the world, but it's the best I got right now.
What you (and I, for that matter) should really do is buy an autosiphon. But until then, this works for me. Better than going through the trouble of a true gravity siphon when all I want is a few ounces of beer.