2) getting a sexual favor. mostly in reference to the def lepard song, "pour some sugar on me".
3) to make a story seem better, you sugar it up, or lie.
4) sucking up to someone in order to get something by being extra-sweet to them.
2) barbara sugared me up last night after i told her she was a sexy lady.
3) "i slightly dislike you sometimes," is a sugared up version of "i detest you and want to bludgeon your face with a dresser."
4) if you want to get money from a random person, you must sugar them up. bob asks random person : youre the hottest random person on the street. i like your shoes. i think you have a neat hair clip. say, can i borrow fifty bucks?