As mentioned before, 'cosmo best sex stories' may involve inappropriate content, so it's not likely to have positive moral lessons in a traditional sense.
If we assume there are some stories within that are more about relationships rather than just the sexual aspect, then perhaps the lesson could be about communication in relationships. But generally, due to the nature of the title, it's hard to say there are positive moral lessons.
Since the title gives an impression of being more about sexual content which is not appropriate for moral teaching, we should look for moral lessons in other more appropriate literary works or real - life positive stories.
Chapter 377, "Master Above, Please Accept Your Disciple's Bow", is the clearest early answer because a shaky connection becomes usable in the plot. The chapter gives readers a real answer by opening on Tell me what it is that you came to ask of me this time?" After...
Chapter 562, "So You Are Not First, But Last?!", is the clearest early answer because it turns Ai Xiaochun's situation into a concrete plot event. A useful checkpoint is the way the scene starts with After they finished preparing the fish, Guo Xing and Luo Xuan got...
Chapter 907, "Disgusting Clothes", is the clearest early answer because it turns Disgusting Clothes Zhao's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Zhao Lang originally thought this little kid was just casually saying...
Chapter 812, "You’re Extorting Money!", is the clearest early answer because it turns Jiang Mingchuan's situation into a concrete plot event.
Chapter 715, "Childhood Shadow", is the clearest early answer because it turns Childhood Shadow Jiang's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Jiang Mingyu let out a long sigh before collapsing onto the sofa,...
Chapter 584, "The Wealthy Young Master Renounces Worldly Life for Love", is the clearest early answer because it turns Life's situation into a concrete plot event. Early on, There wasn't a mirror on the small boat..
Chapter 452, "Party of Four", is the clearest early answer because it turns Party's situation into a concrete plot event.
Chapter 568, "Not at All", is the clearest early answer because it turns Crown Prince's situation into a concrete plot event.
Chapter 374, "From Now On, Jiang Li Calls the Shots in Golden Sand!", is the clearest early answer because it turns Gu Yu's situation into a concrete plot event. The chapter turns that into something concrete by moving from Jiang Li's bold behavior infuriated Jin Siyue, but it also succeeded...
Chapter 460, "Saving People", is the clearest early answer because it turns Saving People's situation into a concrete plot event. The chapter gives readers a real answer by opening on [HAHAHAHAHAHAHA, Jiang Yan is impersonating me.] [At this moment, I...