Jungkook never had kissed someone before, he never even held hands with someone other than his hyungs in a way idols sometimes do. Means, fanservice.
And here he was, sucking on Taehyung’s neck, his hand palming over the others crotch. It was awkward, Jungkook was nervous and way too inexperienced for this, but the feeling of this was just too amazing neither of them was able to stop.