For armpits, dry your armpits Insert the tip of the bulb around the armpit, clamp it tightly for 3-4 minutes, then read the temperature.
For mouth, insert the tip of the bulb under the tongue. Close the mouth and do not chew or bite to prevent the mercury from cracking. Wait for 2 minutes before reading the temperature.
For rectum, Dip the tip of the bulb into Vaseline or oil. In order to lubricate it without pain, gently insert the tip of the bulb. Should not insert more than 1 inch deep. Wait for 2-3 minutes before take out to read the temperature.