Kimochi is not just use for porn, is a basic expression when we feel about something emotionally, either a happy feeling, comfortable, disgusting, pleasant, sad etc. So it's more meaning of feeling. Such as we feel the warm of sunshine that make our feelings feels good because of the beautiful day. So we will say "Yoko, kimochi-ii desu (The sunshine feels good)". Or there is a feeling that we cant forget (either is sad, angry or happy etc) we will say "kono kimochi zutto wasurenai (i will never forget this feeling)". Or u feel something so deeply n truly from ur heart, u will say "hontou ni kimochi (true feelings)"

But people outside japan (not just in korea, but around the world lol) who watch JAV, usually will use this words for a dirty joke because japanese porn star always said "kimochi" when they are having sex (coz sex make people feels good).