Final answer:
For immunizations, preschoolers should be seated on a caregiver's lap and use a shorter needle to minimize pain and provide comfort.
Step-by-step explanation:
When administering immunizations to preschoolers, one recommended position is seated on a caregiver’s lap. This position offers comfort and a sense of security to the child during the procedure. To minimize pain and discomfort, using a shorter needle is suggested. This allows for a quick and precise administration into the muscle with less pain. The goal is to make the experience as less traumatic as possible for the child, promoting a positive association with medical care and vaccines, which are critical for preventing serious diseases such as whooping cough, measles, and polio.