You wouldn't if it wasn't for an unexpected distraction for the lusty elf.

You shake your head and clench your teeth, trying your best to hold yourself back as Instructor Shyael's bountiful bosom engulfs your rigid rod so pleasurably. You think, though, that you just won't be able to keep yourself from losing control. You are but a young man being pleasured by the academy's most lusted after figure, after all. The fact that you've lasted this long at all is a wonder and you know that, if she keeps going, that wonder will cease very quickly and end with you shooting your thick load all over the beautiful elf's face and breasts.

Which, if you really think about it, isn't an altogether unpleasant prospect.

Before you can follow that line of thought to it's inevitable conclusion, your instructor's actions suddenly stop as her body shudders and a throaty moan leaves her lips. You look at her in surprise (and more than a little disappointment) as you try to see what it is that has stopped her actions. What it is is very clear as you see your familiar, apparently still as eager and lustful as ever, burying her face in the elf's upturned rear end. You can't see from your position what she is doing, but, judging from the pleasured expression upon your instructor's face and Lime's propensity towards lapping up sexual fluids, you can guess that the flexible and talented tongue of the slime girl is hard at work at the elf's dripping pussy.

"Aaaah~! Th-that's....goooooood!", the aroused elf beauty moans out as your familiar (presumably) licks and laps at her wet womanhood with the same gusto she showed in suckling at your manhood not too long ago, causing the elvish beauty to shiver and wiggle with every delightful bit of attention Lime gives her. This has the added bonus of causing her breasts, still wrapped about your manhood, to shift and squeeze around your shaft, though not with nearly the same intensity as before. It is pleasurable, but manageable and gives you enough time to rein in the very strong urge to climax that had been so very close to overwhelming you. In fact, you believe you've gotten yourself almost to a state you could call calm when, suddenly, Lime does something that throws calm right out the window.

The slime girl slowly rises up to her knees behind the busty elf, causing Instructor Shyael to whine girlishly at the loss of the tongue pleasuring her orally. If she could see what you see, however, she might have been squealing in delight instead. For, before your wide and surprised gaze, Lime seems to shift and move the slime that makes up her form down towards her groin. You see her normally translucent green hue darken at that area and, suddenly, begin to distend and extend forward. You can only look on in disbelief as an appendage begins to grow there. An appendage that you could only call, as it begins to coalesce into a more solid form, an erect penis. Actually, if you looked closely (or as closely as you could from your place on the floor looking over the lovely slopes of Instructor Shyael's buttocks to see your familiar), you would have to say she had formed and appendage that was identical to YOUR erect penis.

"Wh-wh-when did you learn to do that?!", you gasp out as your familiar gives her new hard member an experimental stroke, something that seems to please her as she shivers in delight at the action.

"Learn to do what?", your instructor asks and starts to look over her shoulder to see what it is Lime has "learned"...and looks back just in time to see Lime put that unexpected knowledge she has just exhibited to good use!