"In the third part of our experiment, which you are here for now, we will be putting an endotracheal tube in your windpipe, the same size that was attached to the end of the spirometer mouthpiece last time. The stationary bicycle will be set up as in the two previous sessions". Sharon nodded, remembering the many briefings she had received during the course of the study. Sharon thought, "Yes, yes, let's get on with it! I'll never sign up for physiology extra credit again if it's gonna be like this; over and over we're gonna do this, that and the other thing to you!". "Sharon?" The grad student was staring at her. "Wha?..oh, sorry. Last food by mouth, 7:30 last night" Sharon replied. "Good. Let's get you to the prep room". The grad led Sharon down the familiar hall to a small room next to the ergonometry suite. Sharon took a seat and took in her surroundings. She heard the grads in the other room, busy with another subject/student apparently in the same experiment as herself. Sharon heard the bike slow to a stop and the usual sounds of air moving through the spirometer tubes, disconnecting electrodes and a demand-valve oxygen regulator that the grads used when the maximal-work tests were over and oxygen levels needed to be boosted. She recognized Jill, another student seeking extra credit, as she was helped into the prep room. The usual mask for oxygen wasn't covering her face though, but she recognized the tube in her mouth as the same one she was shown earlier. "So, that's what I'm in for" Sharon thought. Jill laid semi-reclining on an exam table, breathing through the tube in her mouth that was connected to a humidifier circuit. The grad that led Sharon in said "Come on over, this is the best way to show you what to expect". Sharon came over, "Hi, JIll!", Jill waved and folded her hands over her stomach. "We will let you rest here until it's safe to extubate you, Jill," The respiratory nurse said. The RN spoke, "Sharon, you will have a tube like Jill's, passd through your mouth," gesturing along Jill's throat, "and into your windpipe. Then we'll tape it in place and let you ride the bike until you can't anymore." Sharon nodded, perplexed at the feelings she was having as she watched Jill lying there breathing, eyes closed, the raised pulse showing in her neck. Jill had modest breasts, rising and falling with her extra breathing effort due to the endotracheal tube. Sharon liked looking at pretty girls like anyone else, but that tube did something to Jill's features that she couldn't describe. "Now it's my turn," Sharon thought "I wonder how I will look..." They started by spraying an anesthetic in her throat, then Sharon breathed a nebulized solution to numb the throat more. After a few minutes, Sharon laid back on another exam table; monitoring electrodes were placed on her chest and an oxygen sensor on her finger. She heard Jill, trying to cough. "It's all right, she's just getting feeling back in her throat, it's time to extubate her" the resp nurse said. Sharon craned her neck to watch, seeing JIll's tape being peeled off, a syringe being pulled, and the tube gently lifted from Jill's lips. Someone attached a clear mask to the humidifier hose and put it over her nose and mouth. Sharon felt a little, wet, really, must be nerves. The resp nurse came over, "Now let's give it a try on you. Open wide.." Sharon complied, feeling a cool smoothblade push her tongue up, as well as she could with the anesthetic. She looked at the nurse's chin, the glanced down/up to see her tube sliding into her mouth. The tube looked so big! "Breathe deeply for me, that's good," Sharon felt the tube push her throat down a little, then it slipped past her vocal cords with a bump that made her twitch. "That's okay, I've got the tube in you now,' and the nurse removed the laryngoscope blade. Sharon heard her breath rasp in and out through her tube, feeling a small gagging sensation like she inhaled a drop of water. "Now I'm going to inflate the cuff. You may feel a little pressure" the nurse instructed. Sharon did feel the cuff filling, like a swallow halfway down her throat. The nurse held the tube while a grad student applied tape, using several strips to hold the tube firmly in her for the experiment. Her thoughts raced: "I've had dildoes deep in my throat, but this is so different, I can breathe with this fullness in me". Sharon didn't notice the other effects all this excitement was having on her until now; she was noticeably wet, her nipples pushing up into her 37D-cups, her breathing deeper than before. She laid on the table, adjusting to her tube, glancing at Jill who looked back with a knowing smile She saw Jill sneak over to a tray, and snatch two tubes and a syringe and stuff them into her purse, then hop back into a chair with a wink. Sharon reflexively reached up to her face to feel the tube sticking out of her mouth, and the tape holding it there. She put a finger over the end, feeling her breath whoosh in and out, catching with her heartbeat. "Sharon, don't pull the tube", the grad student said. "We're ready for you in there." Sharon was helped up and into the ergonomics suite. She hopped onto the bike and put her feet on the pedals. Grads connected her electrodes, and the monitors clicked with her pulse. The spirometry tube hung in front of her, gray and wide. After a few adjustments were made with the equipment, Sharon's tube was snapped into the spirometer's connector. "Okay Sharon try not to move your head too much while you pedal, begin now and keep the RPMs near 60" the chief grad student said. Sharon nodded slightly, feeling her tube tugged by the spirometry hose. She started pumping the pedals, feeling the bike seat rub her vulva as she went faster. She breathed in and out through her tube, resistance making her more breathless. She tried to focus on the test, staring straight ahead but the seat was meeting her leg's efforts and returning the favor. She was wet, so wet, her tube sliding up and down in her throat ever so slightly like a living thing. She hopped on the seat with every pedal push, bumping her clitoris in a barely-thinking attempt to cum. Spittle slid out of her mouth under her tube and splashed onto the bike's frame. The grad students looked on in false disinterest, or busied themselves with reading gauges of some kind. Sharon didn't care. She wasn't even thinking. She was awash with pleasure on a plateau within reach of... "Sharon! Slow down!! HEY!!!" Sharon snapped back, suddenly exhausted. Grads on each side of her grabbed her upper arms even before she realized she was faint. Quickly she was disconnected from the spirometer and electrodes, but the oxygen sensor was left in place. Sharon stumbled off the bike, aided by the grads until she could stand reasonably well on her own. Someone connected her tube to a demand valve and she began inhaling pure oxygen. More spittle ran down her chin, which was quickly wiped up. Regaining her senses a little, she was led into the prep room and onto the table Jill had been on before. Her oxygen valve was replaced with the humidifier. "Sharon, we need you to wait here until the anesthetic wears off and we can remove your tube"; Sharon nodded, feeling the tube in her throat more than before. Sharon made writing motions, and the nurse produced a pen and paper. "Bathroom. Have to pee." "Can you wait 'til we get that tube out?" the nurse asked. "NO" she firmly shook her head. "Alright. I'll walk down with you. If there's any trouble though you need to come out immediately." They quickly strode to the women's restroom, and Sharon went in. The facilities were empty save for herself. She walked over to the mirror, slowly turning to see herself. Closer, she bent to the mirror to see her lips obscured by whitish tape that went from ear to ear, corner of the jaw to the other, encircling her chin. The tube, the object of her new-found fascination, held firmly to her lips and into her, deep into her mouth and throat. She brought a hand up to stroke her tape-covered mouth, feeling the tube and tape as never before, not like in the prep room. She caressed the tube and her face around it, as her other hand slid into her panties to rub her still-hungry clitoris and probe her wetness. She went to the nearest stall she could sit in and still see herself in the mirrors. Straddling the seat she began rubbing the lips of her vagina near her clitoris, stimulating herself with her shaky fingers. Her other hand spread her vaginal lips as she slid two fingers into herself, the thumb now in perfect location to rub her clitoris. Working in and out with her fingers and thumb, she almost slapped herself in the face trying to feel the tube, her tube now so fully present and filling. Breathing hard, her tube was unrelenting in it's strangulation/not-strangling, making her already breathless state ecstatic. Sharon's fingertips caressed her tube, making her gag just a little; she couldn't delay herself anymore, eyes rolling back she finally brought herself to orgasm! Minutes passed. As she withdrew her fingers from her fatigued vagina, she got a little orgasm. She saw herself in the mirror, looking very flushed and blushed in abstract patterns. Sharon noticed a cough developing, it was time to go and get extubated. Quickly washing her hands she left to find the nurse chitchatting with a grad student. She motioned to her tube, and the nurse knew what that meant. They went back to the prep room. Sharon was fully aware of her tube, coughing silently through it. The nurse quickly suctioned spittle from Sharon's mouth, the added "Sharon, I'll take off the tape, then deflate the cuff. Then I want you to pull out the tube when you feel ready, but don't wait more than 30 seconds. Here, take a hold of the tube but don't pull yet!". The nurse quickly but gently removed the tape from Sharon's cheeks, then attached the syringe to the pilot balloon that would deflate her cuff. "Ready, I'll count to three then you can pull out the tube on your next breath...1,2, (the nurse deflated the cuff and quickly checked to make sure it deflated), three!" Sharon felt the cuff deflate, the fullness replaced by some irritation. She breathed nervously once, exhaled, breathed deeper then tugged the tube. She felt her tube pass her vocal cords, then swiftly pulled it the rest of the way out. Attempting to speak, she coughed instead. "Here's some humidified air, you need to breathe this for a while until you feel less irritated." A half hour later as she prepared to leave, Sharon looked at the intubation tray on a stand next to the exam table. She thought about taking some "mementos" . She noticed five more tubes there, obviously expecting more subjects. Everyone else had gone to lunch, the next experiment wasn't due for two hours. "No, this was something I'll never forget and never have again," she quietly spoke to herself. She left the building in an uncertain mood. Passing the smoker's cloister, she jumped as she saw Jill quietly smoking a pipe. "Hi Sharon! Did you have fun?" Jill said between puffs on her quarter-bent pipe. "Jill!" Sharon said roughly, words catching in her throat, "I didn't expect to see you here. Why the pipe?" Jill responded, "My throat's too rough for cigarettes, so I borrow my uncle's pipe every year so I can smoke after these experiments." "Every year? How long has this been going on?" "Since I've been a student here, two years. This is my third time!" Sharon's jaw dropped. Seeing that expression told Jill all she needed to know. "Let's get some lunch, I'm buying!" Jill said as she tapped out her pipe. Sharon could only close her mouth and catch up.