Hey again Cooties are imaginary germs that are said to come from the opposite sex.

Cooties -> Those annoying "bugs" walking on your head. :D

Cooties is a made up disease, children use to avoid one another. Cooties is "contagious", so when one child doesn't want to play with another child, they spread a story in school, for example, saying he/she has cooties, and that's why they don't want to play because they don't want to catch it. Because cooties is "contagious", someone who plays with a child labelled with cooties is also said to be "infected", and therefore avoided.