Her mother, Christine.

Heading downstairs, Nat crosses the house to her mom's office door. She can hear the telltale mechanic hum of her mother at work, so she knocks first and hears her mother call, "Come in!"

"Hey, mom," Nat says as she slips into the office. Dr. Christine Pierce glances over to her daughter with a smile. She's holding a large, broad paintbrush.

"Hey Nat! What's up, honey?" Dr. Pierce leans down and applies the brush to the quivering pussy of the petite Asian girl cuffed on her back who lies on the professor's desk. The girl gasps and jumps slightly, letting out a needy little whine as the professor coats her labia liberally with cum.

"I'm gonna head over to Anna's to hang out for a bit," Nat informs her. Her mom steps over to the third girl in the room, a redhead with freckles spreading all the way down her chest who's strapped to a running Sybian. The girl is heavily flushed, and drool is oozing out of her mouth around the penis gag strapped to her head. As Nat watches, her mom dips the paintbrush into a small container of cum and paints the redhead's tits with it. "What's this for?"

"Oh, just an early draft of an experiment," Christine says cheerfully. "I thought it might be interesting to see what effect - if any - clitoral stimulation had on a woman's susceptibility to NFE via ejaculate skin absorption. The boys in my classes were happy to contribute the needed material, and Sara and Katie here are both in freshman seminar and needed a bit of extra credit. Say hello to my daughter Natalie, girls!"

The Asian girl raises her head with a struggle. "H-h-hi Natalie, I'm Katie," she gasps. "P-p-please Dr. Pierce, please let me do something! Please touch m-me! Please!"

"Do I need to gag you like Sara?" Nat's mom asks with a scowl. The redheaded girl just shudders, eyes rolled back in her head. {if Sluttery >19}Nat can feel her own core warming and moistening as she looks at them.{endif} {if Sluttery > 39}I wouldn't mind being strapped to one of those things for a bit...{endif}

"Anyway! Sounds good. Don't forget to wear your choker!" her mom says with a smile.

"Oh, that's right." Digging in her pocket, Nat pulls out her green choker. It matches the ones around the two other girls' necks; up in her bedroom she also has a red version, which she'd worn while she was with Teddy, and a black one, which she's never put on. Her mom smiles.

"Good girl. Have fun!"

Nat nods and starts to exit, then hesitates. She's still trying to process all of her summer reading, and here she's got her mother - a professor of female and gender studies - here in her own house. Maybe I should check in with her about the things I don't understand...