Simplify the following text for a Grade 10 native English-speaking person.
Original: Casual sex means some types of sexual activity outside of a romantic relationship . The term is not always used the same way : some use it to refer to any extramarital sex outside of marriage , some use it to refer to sex in a casual relationship , and others use the word for one-time encounters , promiscuity , or to refer to sex in the absence of emotional attachment or love .
Simplified: Other terms sometimes associated with casual sex include recreational sex and social sex .