Sandy Rustin had a tough time saying goodbye to her oldest son on his first day of preschool a few years ago.  Surprised by her reaction to this milestone, she expressed her feelings by writing a poem about it.  Channeling her emotions into words was constructive, and turned out to be the germ of a project that will be fully realized next week.

The poem eventually evolved into a sweet song called “A Prayer for Ellie” — part of the new musical “Rated P,” which will debut at the South Orange Performing Arts Center (SOPAC) on May 5.

Rustin—who lives with her husband and children in Maplewood — developed the bones of a sketch comedy musical on parenting and teamed up with musician and lyricist team Dan Lipton and David Rossmer to write the show.

The tag line describes it as “a new sketch comedy musical about parenthood that celebrates the wonders and lunacy of raising kids from conception to college drop-off.” It’s a clever and sentimental look at childrearing that is extremely relatable. Rustin says that was definitely the goal. “The show should resonate with anyone who’s ever had a parent or who is a parent.”

Rustin showed up for our interview wearing an Oxford shirt and jeans — a typical costume for her role as mom to two boys, six year old Isaac and almost two year old Charlie. At 35, she has the fresh face and broad smile of an actress, and her enthusiastic annunciation hints that she’s a seasoned performer.

She’s got the chops. Graduating from Northwestern University with a degree in theater, her professional credits include Sandy in the national tour of “Grease,” and “I Love You, You’re Perfect, Now Change” in Chicago. She graces several improv stages in New York and has appeared in TV roles, including “All My Children,” “Guiding Light,” and “Law and Order: SVU.”

On a break from acting after Isaac was born, Rustin started writing to keep busy while he napped. A teacher from her sketch comedy class offered some advice that got her started on the path to playwright. “My teachers said ‘Write what you know. Find the funny in your every day.’” What’s more comical than explaining sex to your kid or realizing your middle schooler is smarter than you are?

By the time Isaac was three, Rustin had about 50 pages of sketches detailing the amusing anecdotes and poignant moments abundant in the parenting experience. She showed them to Lipton and Rossmer — two friends from Northwestern — to see if she had something. The creative duo recognized the seeds of a musical and agreed to work with Rustin on what eventually became “Rated P.”

Two actors and a pair of actresses play some 80 characters — from kids to grandparents — over the course of the show. True to the tag line, it begins with a stressed out couple trying to survive labor pains and ends with a mom trying not to lose it while dropping her daughter off at her college dorm.

Originally, Rustin thought she would play one of the female roles but her collaborators warned that it would be difficult to wear both acting and writing hats. Owning the role of writer was an adjustment.  

“I’m used to being an actress and getting an immediate response from the audience. When you’re writing it’s just you….you’re not sure if it’s meaningful or relevant…. you don’t get feedback until it’s in front of an audience.”

The positive support was likely worth the wait. Rustin sat in awe in the back of a full theater during the first public reading of the show at SOPAC last August. “It was just overwhelming….hundreds of people laughing at something I helped create…or crying because of an idea I had. I felt very emotional and grateful. Seeing your idea brought to life is very exciting. “

At around the time of the reading, a group of local actors, writers, musicians, directors, and producers — many from Maplewood and South Orange — were coming together to form a new theater company in residence at SOPAC. Rustin is one of the founding members and Co-Creative Directors of Midtown Direct Rep, which aims at showcasing Broadway talent and forming a theater community outside of New York. 

“We created Midtown Direct Rep because all of us live here to be away from the hubbub of the city and live a normal life. But to have space so close to home in a safe, creative environment — it’s awesome. It’s become a source of comfort and fun and friendship.”

The group was looking for pieces to perform this year and a fellow member proposed “Rated P” as a good fit. Rustin, Lipton, and Rossmer got to work reshaping the show for a wider audience. 

As Rustin suggests, they wanted to resist the temptation to complain or take a cynical view of parenting… and focus on the positive and moving aspects. “The show is a moment to say look how fun and awesome this time of life is…it’s a reflection of the funny and sweet parts of parenting.”  

When the show’s short run ends, Rustin will no doubt be back in her jeans pushing a stroller and coming up with new sketches, while trying to balance work and family. Next up, she will be covering actress Julia Stiles in Neil LaBute’s “Fat Pig,” coming to Broadway this fall.

“Rated P” runs May 5-8 at SOPAC. For tickets visit SOPAC or call 973-313-2787.