The term Netflix and chill was derived from the old saying "want to come over and watch a movie?" In the teenage world, that
almost always meant that the parents were not home. This, in turn, would lead to
sexual acts by the
impulsive, hormonal young humans. Now in day, the term has evolved to Netflix and chill, as it is the new way of inviting your partner over to be together alone, but both of you know, although you might not say it, what it will lead to. Hence, the term can now be used in place of the word "sex".