For people who are single and looking on the Dating scene it has always been a question of when first time sex is okay. It has always been nominally part of the Dating etiquette to assume that if a guy buys dinner and pays for everything then there should be something back. It isn’t always sex right off but could be a kiss or some fooling around in the middle. This is naturally provided that the girl is attracted to the guy and he has acted as a gentlemen. It’s also assumed that if the guy is pushy then all bets are off.
If however he has done everything right and hasn’t made any assumptions then it is typically incumbent upon the girl to do something. This is as true with gay and lesbian dating as well.