She cums on the spot

When the mature succubus nibbles on Kasha's pointed elf ear, the adventurer helplessly cums on the spot.

Miss French pulls away, leering down at Kasha. "Oh my, is that all it took to make you cum? But I've just gotten started~" She pursed her lips, once again leaning down until hers were a hair's breadth from Kasha's, lingering there for several long moments, before she turned her attention towards kissing her way up Kasha's neck. The elf moaned and squirmed, already heating up again after her first orgasm, the magic infused kisses turning her on. Miss French continued up the side of her victim's face, finally reaching her ear, and softly licking the tip.

Kasha was helpless, cumming again. She was already laying in a puddle of her own juices. And too weak to resist.

"It should be clear you've failed the assignment, but I'm going to give you a chance for extra credit: If you cum less than a dozen times in the next hour, you pass the class. I'll even play by the previous rules and only touch you from the shoulders up~" She blew in Kasha's ear, and the elf squirmed, rubbing her thighs together. "This is such a generous offer, I'm not letting you turn it down~"

Kasha opened her mouth to say something, she wasn't even sure what, but Miss French swooped in. Her tongue founds its way into Kasha's mouth, and she began vigorously making out with her captive. The powerful lust magic the succubus could wield made the elf's eyes roll back in her head, as she was promptly swallowed up by pleasure.

***

An hour had passed, and Kasha had just had her fiftieth orgasm in that time. Her brain was completely fried.

The nerdy succubus was still blushing as she made out with the doll, having been ordered to keep up the assignment. The other two succubi were still dueling with their tongues, neither willing to give up.

As her students continued, Miss French dragged Kasha's limp form over to her desk. With a snap of her fingers, all of Kasha's clothing burned away. Miss French then opened her desk, and removed a ring gag from a drawer. She secured it into place, ensuring Kasha's mouth hung open for anyone to use. She then locked the elf's arms in a leather armbinder, and dragged her back over to the desk the adventurer had first sat down in. With a pair of cuffs, Miss French was able to secure her captive to the desk by the ankles.

This left the blonde elf as a permanent student of the class, one who'd be available to any number of students, and to the professor in between classes. And she'd sit there, brainless and available to kiss, for the remainder of her mortal life.

Bad End