"Well. let us get down to business! This is my first day and I would like to get to meet some of my student body! You! Secretary, come here!"
She sheepishly comes closer. After all, yo0u just gulped down the headmistress and she gives you the respect you deserve. "Yes, Headmistress?"
"Stand up straight. I am not going to eat you...Not yet any way. But first I want you do do something for me. If you do your job, you will not have to worry about being eaten...By me any way."
She gets more confident and shoots up straight. Her D-Cup cleavage is a very tasty sight and gives you an idea. "Yes, Ma'am! You can count on me! I am the only one of my clone group that has lasted this long, and the last headmistress ate the original, so I am the last of my breed. And I plan to get out of this semester and on with my freedom! So, I will be at your service for WHATEVER you want me for!"
"I like that," you smile at her new found moxie, a clone with a chance at freedom is a very useful ally. And if she has survived this long... "Excellent. I will sign your letter of dismissal if we both make it. And now, I want you to get me my next meal!"