Susie Essman launched her memoir, “What Would Susie Say?,” with friends Joy Behar, Jeffrey Ross and Richard Belzer the other night at Caroline’s on Broadway, where she recalled the early days of “Curb Your Enthusiasm.” She told The Post’s Mandy Stadtmiller, “We didn’t have trailers. That’s unheard of. After Season 2, for two seasons we had a communal trailer that we all shared — me, Larry [David], Jeff [Garlin], Cheryl [Hines], any of the guests stars, we were all in the same trailer. Changing together, using the same bathroom. You think those ‘Sex and the City’ girls didn’t have trailers from day one? Oh yes they did!”