“So what does a factorial look like and how do you calculate it?”“That’s like… a number with an exclamation mark after it, and… you calcul...te it by multiplying it by every number below it.”“Good, okay. What’s a permutation?”“Um…” She struggled a bit more with this one. “Like… a combination but…” She sighed. “I um… I forget. Could we go over it quickly?”There was a lot of work ahead of us. * “So the answer is…” I trailed off. Taylor sat unmoved for a bit. She wrote a few things down, filling in. "Um, Mandy, nice job tonight. Uh, Steve Parsons has told me that you are an exceptional babysitter and like to make sure that the everyone is happy with your work, especially the father." Without waiting, I reached over and put my hand on his bulging lap and said, "I'm sure I can make you happy, it's part of my service." "Well, well, um, let's see, well, fifty dollars seems a good amount for making me happy. Is that all right with you?" "Yes, that's fine," and he got out five tens which I put. She straightened Nikki up and pulled her mouth open to spit the large amount of cum from her own mouth into Rachel's. She hardly gave Nikki a chance to taste it before grabbing her by the hair and holding her face over the rim of the glass and making her spit the contents of her mouth into the glass. The cocktail was coming along nicely! Hungrily eying the concoction and licking her lips Nikki allowed herself a moment to stare across the room at her Mistress, Carissa, taking on three men, not. Pretty sure my record was four guys fucking me one night at the first sex party I was invited to with those guys. My text to Alex was "Four"His reply back.... "Want to double that number?" I can try, thanks for the heads up I'll do some stretching before hand."For the rest of the week, I was pretty horny thinking about what Alex and Adam had planned for Friday's sex party. I did my stretches, making sure I used my butt plug daily.Friday afternoon finally came around. Some of the boys that Alex.