Noct shouldn't be a virgin on his wedding night. Luna sent him someone to take care of that on his birthday.

Birthday should be at least 16. Fun sex, NO rank issues (Noct is a Prince), and the person teaching doesn't fuck Noct up (they're enjoying teaching and not in a nasty way).

+1000-She sent him twins; one male, one female.
++Noct figures out how to use magic during sex. (how is up to you)
+++No one figured out exactly what Luna had sent Noct until a while later. (I love reactions)