i ride 44/16, and 49/17 and can skid on both. on the 49T bike i would have to lean forward more if it didn't have a 650c front wheel. brand new kevlar tires will skid a lot easier than non-kevlar tires...the panaracer tourguard and the michelin axial kevlar come to mind. armadillos tend to not skid quite as well as those, but they still skid....the hutchinson carbon comp tire skids VERY easily, but also leaves about half the tire tread on the pavement after each skid.

tires with tiny nubs tend to skid easier for me and let out kind of a howl, or WHIIIIR noise.

leaning a bit forward, or putting your hips closer to the handlebars can help make skidding easier...and once you can do the basic straight skid, you can learn the fun turny-type skids that can help you evade danger.