With degrading and painful sex

A sudden thought strikes you and you ask your lovely grad-student whether she has a hairbrush with her. Sure enough, she produces a flimsy plastic thing from her bag, the sparse black bristles ending in little round bobbles. It's not in any way suitable for a spanking, but fortunately the right shape for what you have in mind.

Imogen stands facing you, weeping quietly, her hands behind her back as she awaits your next instruction. You reach between her legs and roughly part her sensitive labia, worming the head of her brush between, before unceremoniously shoving the object up into her tight little twat. The young lady stifles her scream and if she could raise herself any higher onto her tiptoes, you're sure she would.

"Turn around and fuck me hard and fast with your arse, Imogen."

"Yes, Professor," she sobs out, wretchedly, hastening to open your fly and obey.

With her cunt overfilled by the prickly intruder, Imogen's rear passage is almost uncomfortably tight, but you bear the intense sensations stoically. She reaches behind herself to grab the back of your chair, so that she can use it as leverage to slam herself down on your cock, hard and fast, like you demanded. On the first descent, she lets out a strangled cry, when the handle of the brush impacts the seat of your chair just as her abraded buttocks collide with your lap. She lifts herself once more, driving herself back down mercilessly, cruelly torturing herself for your pleasure.

It's this willingness to suffer for your gratification, even more than the skilled application of her anal muscles, that rapidly brings you close to climax, but you selflessly hold back, prolonging her agony to show that you don't find her enchanting beauty and charms irresistible. Still, you don't last long, her wracking sobs pushing you over the edge and allowing her bruised arsehole to milk the awaited orgasm from your pampered prick.

Sated, you slump against your student's back for a moment, gathering your strength, before giving her a playful slap on the thigh and dismissing her. She extracts your member from her throbbing hole and kneels to take it briefly in her mouth and ensure no trace of your recent activity remains, then slips it tenderly back into your pants, before quickly putting her clothes in order and showering you with thanks, the handle of her hairbrush protruding lewdly beneath her hemline. She hesitates, clearly wondering what to do about the unwanted intruder, but unwilling to ask, so you take hold of the offending object and give it a brutal twist one hundred and eighty degrees. Imogen wails piteously and almost collapses, but somehow manages to save herself, so you give the end a tap that sends excruciating shockwaves through her twat and tell her that she can remove it after lunch.

The tormented twenty-something sobs out a final thanks, gathers her things and leaves, only slightly less elegantly than she entered, despite the awkward accessory wrenching inside her with every step.