Movsesian, longtime assistant to Conan O’Brien, takes a riotous look back at her 13 years working with the legendary late-night host, while sharing the often hilarious lessons she learned along the way in The World’s Worst Assistant (Plume, July).

You’ve been Conan’s right-hand woman for 13 years. Why write a book about your friendship now?

I never thought about writing a book until a friend of mine encouraged me to go for it. I think the reason it felt right to do it now is because I’ve noticed that people’s attitudes toward their work is changing and they tolerate a lot less in terms of mistreatment. The stereotypes for personal assistants, especially when you assist someone who’s really high up, is that you have to sacrifice so much of yourself for your job, but I never had to do that. I was very lucky because I worked for someone who was a decent human being. He never mistreated me aside from smacking food out of my hand. What happened throughout my time working for Conan was I realized that I could parlay the job into something that is fulfilling for me. I love going to work every Monday.

It’s not everyday that someone tells their boss to “stop being a bitch” and walks out of the room still employed, yet you’ve managed to carry on a decidedly unprofessional relationship with Conan for years now. How did this dynamic develop between you two?

Over the course of time, he and I just both started testing how far we could both go with one another. He would make a joke about me and then I’d laugh, so he would know that that’s allowed, and then I’d say something that was slightly unprofessional and he would respond to that in a not negative way, so then I’d think, “Oh, then that’s allowed.” I think the best way to describe it is if there was a giant piece of marble and both of us are chipping away at it, at this point there would be nothing left. We’ve gotten to the point where Conan has begrudgingly accepted how unprofessional I can be, but I also have accepted how my nonprofessionalism could be fodder for him. I think both of us get something from not being professional.

Throughout the book, you offer guidance to readers looking to break into the entertainment industry, including the memorable directive “don’t let someone shit in your mouth.” If you could narrow your ethos down to one takeaway for readers, what would it be?

I can’t wait until my mom reads that part. I really hope we get to a point where people start to realize that they’re worth more and that they don’t need to be mistreated at work. I hope people read the book and feel like they are worthy of a lot more and that they are worthy of being respected by the people they work with and for. Also don’t let someone shit in your mouth—literally and figuratively—unless, that is, you’re into it.