Of the nearly 200 varieties of condoms available today, only eight of them feature any deviation in size—either a little larger or a little smaller. But Condomania has recently introduced TheyFit condoms, prophylactics custom-tailored to your penis size ($12 a dozen). "With condoms, size definitely matters," says Adam Glickman, president of Condomania.

The process is simple: Go to condomania.com and print out a "fit kit." Cut out the penis pattern and use it to measure your length and girth, then choose from 55 sizes (length goes from 3 inches to 10 inches, girth from "super-slim" to "extra-roomy"). Send your numbers to the secure site and then wait for delivery.

Are they worth it? "The difference is amazing," says our tester. "It slid on in a single stroke, and instead of anchoring itself with a pinching roll around base camp, it simply adhered to the entire shaft, second-skin-style. Once you've been custom-suited, an off-the-rack condom feels like punishment."