Accept her proposal, with a twist

"That's a very interesting proposal Becky." You get up from your desk and go shut the door to your office. After it shuts you move to the back of Becky's chair, placing your hands on her shoulders. "Now let me get this straight, you are willing to get Sheena to have a threesome with you and myself in exchange for continuing your internship here." You are now massaging her shoulders gently.
"I believe something can be worked out along those lines."
"However, I do not believe that you can guarantee me Sheena, so I am going to need a down payment on your debt first."
"And just what are you asking for as a down payment?"