Each Period may have event related to story available for discover. To do so, press F4 start of every time period for unique NPCs.
Successfully invite an NPC home will result in H. They will leave a memo for the PC next morning before they leave. However, (TBC) Giving them a good H, or invite them the day before the day off will have the PC wake up with the NPC initiate H in the morning (start with a BJ for example)
Going on a date with NPC. More info needed
However, be careful with how many people you accept going on a date with. They will be upset with the PC the next day, and will lose a few action points to successfully apologize to them.