1: n. (Medical Acronym) Self-Auditory Chubs Syndrome. Getting a hard-on from hearing oneself talk. People can have SACS over various topics about which they are passionate or on which they think they are experts.
2: v. To SACS out is to go on and on about whatever gives you SACS.
Professor Smartass totally SACS'ed out today in lecture about his current research.
Mothers of only children have hardcore SACS over their seemingly perfect, precious babies.