What do you do? What is a Doula?

I got asked this about 50 times today while I was standing behind my booth at the Community Baby Shower. How do I explain what a doula is in one to two sentences? My answer seemed to change person to person. "professional labor support person"
"I'm a non-medical labor support person"
" I educate the mom's and find out what her birth wishes are then..."
"I help engage the partner in the process"
"I''m a childbirth educator and a birth doula  and I..."
I felt like I was having an off day and should have planned a line to use. But the truth is you can't explain what doula support is in just one or two sentences. A doula's role changes person to person, labor to labor. I've worked with single mom's, married couples, dating couples, inmates, women of different levels of education and income, first birth, second birth, natural birth, epidurals, emergency and planned c-sections. And my role changed from person to person. Some  of  the women I got to meet with 3+ times prior to birth and was able to give prenatal education, others hired me after there were admitted into the hospital for complications, and I am a on-call volunteer labor support for women from the local prison.
In all cases I leave behind my own views on birth so I am able to support birth for them, because it is after all there birth not mine. I do suggest reading book's such as Ina May's guide to birth, pushed, The Birth Partner. Books that focus on  birth being  a natural process, something as women we are designed to do... We talk about what the clients wishes are and how they can achieve them... educate them on the pro's and con's on interventions so they know ahead of time.  answer questions. find information. If there is a partner of other family members who will be there I show them how they can help mom in labor. I am on-call from 37 weeks until the baby is born. I give my emotional and physical support to the family's. sometimes I'm there for 4 hours sometimes I'm there for 25hours. I  continuously support. For the good outcomes and the not so good outcomes. For the baby's first breath and first "meal". I'm there to answer questions that the new family has in the first few weeks. That is what I do how in the world as I supposed explain all that in one or two sentences?