I had to check prince once and he didn't like it let me tell you!! it's pretty straight forward and maybe dogs are easier. Best to have soemone hold your dog and reassure them while your doing it. First you will need either a ear or what most people use is a rectal thermometer. Put petroleum jelly on it and lift the tail. Insert no more than an inch into the rectum. Hold for 3 mins and remove gently. Your looking for 101 to 102.5 degrees fahrenheit. thats' about 38.3 - 39.2 degrees celcius. Chow for now!!