The Inner warmth and fuzzieness you feel when you're madly in love with someone. When it feels like even the sun and the rest of the universe wants you to succeed.
see: "That Warm Fuzzy Feeling" for similar definitions
Michael: Wow It sure is a good day to be alive, Damn i think I'm in love with that girl Rachael.
Michael's Friend: Lucky fuck, you got a pocket full of sunschein my friend.