Just... Just go along with it

While her barely hidden advances are embarrassing, you don't really have anything to lose from this. You shrug to yourself, and you show her your 'timewaster'.

"Oh wow, hey, that's pretty impressive looking. Maybe I should add this to that study of hard places." She chuckles to herself. "Sorry, that was bad. I'll stop." She unbuttons her shirt and unhooks her bra, letting them fall to the ground on top of the lab coat. Her breasts are ample but sagging just ever so slightly from age, certainly not the largest, but you've seen flatter. "This is the biology lab, lets make some biology happen!" She lowers herself to her knees, though that only takes about a foot off her total height. You lean yourself against a workbench. Her hands play around with your cock, weighing your balls in her palms like a scale, giving them a gentle squeeze here and there. Her fingers gently wrap around the base of the shaft and gives it a tug, running up along and off the head. Giving you a handjob is not what she has in mind for you however, and she grabs her breasts, kneading them a few times for show, and enfolding them around your cock. The envelloping softness and motherly warmth is well, indescribable, so you won't even bother. All you can say is that it feels amazing.

"Heh, you like that big bo-" You thrust your cock in a perfectly timed movement, your balls slapping on her underboob, shoving your bellend into her mouth. She tightens the vice like grip on her breasts around your shaft and spits it out. "Hey! Rude!" she says in an annoyed tone, and then mumbles, "...I was gonna' do that anyway." It's only a moment before the tip of your cock is back into the wetness of her gob. Her tongue tickles your urethra, and her breasts pump away at your itching rod.

It's not long before the pleasure overwhelms you, and with an erratic twitch you blow your load over her squeezed tits and her lapping face, catching a glob with her tongue. A spurt almost hits her in the eye. Your body tightens with every discharge, your hips grinding upwards before a soothing wave washes over you, your body suddenly tired and spent. She greedily licks the remaining gloopy mess off your cock like an obediant little kitten, moaning faintly from the delicious taste. "Mmm... So tasty," she purrs.

It's at that moment that Susanne walks in through the door, and your eyes lock. "Oh hey, you made it! I was worried you might've been cau-" She cuts herself off when she nears you and sees your parner on her knees and covered in cum. "Professor!" she cries, turning her blushing face away.

The professor fidgets in panic. "Hey, this is a biology lab, I was just uh, showing him the uh... an example of how the male ejaculates under stimulation?"

Susanne grumbles, and sighs. "The why wasn't the problem! I just really didn't want to see my professor with her tits out and covered in cum."

"Alright, alright, I get the point." The professor wipes herself with a conveniantly placed roll of paper towels nearby. "Just give me a second. You should probably clean yourself up too." She tosses you the roll.