Your last sentences almost had me ε=ε=(ノ≧∇≦)ノ and the ring is like a symbolism for their connection (yoonsung and jiyon aka hakyung) and the 18+ scenes are basically the more intense make out sesh they had that was cut off in manta version.
It’s the same, or exactly the same as, ring he gave jiyoung when they had their engagement party that summer.
Its hakyung’s engagement ring! We dont know what actually happened with it but i think it meant that yeonsung has regained his memories?
Can someone remind me what's up with the ring at the enf of season two? I don't remember if it was showed before ;__; and also will there be another 18+ scenes in mature version other than the last one? Didn't they have sex for the first time then? Or did I miss something again xd