[ From what I have read, the stage is called "flirting" which describes it pretty well for most of the characters. Apart from Astarion and Lae'zel, all of the main companions treat this stage as a getting-to-know-you stage and are quite serious about their affections.
Typically in classic RPGs, the beginning of an intimate relationship implies the beginning of a romance. So in the case of Astarion and Lae'zel they should have given the player an opportunity for roleplay and a chance to talk to their partner about being together and let the people around them realize it. It's up to the companion how they react, but it would have been realistic rather than imposing on the player that they want to "just have fun".
Originally Posted by ArneBab
The game “teaches” many different lessons on morality depending on the Character and decisions you choose.
Depending on the opinion of the particular author who didn't create the original character. "Losing his soul" - this has already been discussed in dedicated threads, and I can refute it, but it would be off topic here. In other games, "evil choices" don't lead to any perverted sexualized scenes for some reason. "Moral lessons" from a game that offers every possible form of coitus can hardly evoke anything but black irony.