Esprit can be an intimidating experience for a first-time attendee. Esprit's Big and Little Sisters is a "mentoring" program for experienced Esprit veterans (the "Big Sisters") to help first-timers (the "Little Sisters") learn the ropes, get them out of their rooms, take them shopping and generally help them get the most out of Esprit.
If you're a first-timer, perhaps never even out of the closet before, and would like to be paired up with a "Big Sister", check the YES checkbox.
If you've been to Esprit at least once and are comfortable going out and about, AND you have the time to help out a first-timer, check the YES checkbox.