Set her aside

"Mindy, the fuck?" says the brunette.

You take a break from the nipples and look up. "Please strip to your bra and panties and crawl under the table, and please rub your pussy through your panties while you await further instruction."

"Um, OK," she says as she blushes and starts to strip.

"So Mindy, you have tiny tits," you say, "but please realize you have super-sensitive nipples, and please stop wearing bras at college, and please only wear very tight tops with thin fabric."

"OK," said Mindy.

You return to sucking on a nipple while tweaking the other then switching. Mindy's friend is under the table, and you can't see her.

"Please get very, very horny when a man licks, sucks on, or plays with your nipples, Mindy."

Mindy's breathing gets heavier, and she starts to moan. You go back to her sucking and tweaking as Mindy reaches a hand down to her crotch and clenches her jaw.