A good feeling could be 'kimochi ii' (気持ちいい) and a bad feeling 'kimochi warui' (気持ち悪い).
1) This word has been widely disseminated among American otaku due to its prolific use in hentai anime/games, where it is usually translated as 'It feels good' or 'It's good'.
Some romanizations spell it 'kimouchi'.
Antonym: Itai (painful)
2) Used to express the sentiment that an unexpected gift was thoughtful, kind, and given without obligation.
2) A child leaves a basket of cookies on her grandomother's porch; the grandmother might comment to her friend later that it was 'kimochi'.
School girl: "Onegai iie! iie!"
Middle aged man: "Hayakusiro!"
School girl: "Honto oishii soshite kimochi!"
Middle aged man: "Suck my dick you bitch!"
School girl: "Please no! No!"
Middle aged man: "Hurry the fuck up"
School girl: "It tastes and feels really good!"