You look up and down you body and then up and down Taura's larger form and realize you likely need all the precautionary measures you can get.
"Better safe than sorry right?" You respond with a friendly smile. "How about that booster shot?"
Taura smiles back. She radios to her crew to call off the search.
"I have a volunteer ladies. Administering A22 serum and confirming test sequences. If everything is successful, we'll meet you on the bridge," you get a bit nervous at the mention of tests, still unsure of what that meant. But before you can ask, Taura produces a large needle from her utility belt and you go pale.
Seeing your reaction, Taura laughs. "Oh...yeah we weren't expecting you to be quite so small. Let me adjust this," then with a squeeze of her hand, the needle becomes gelatin before reforming in a much smaller size.
"The A22 serum is designed to do to your body what happened to the needle, minus the shrinking part," Taura explained with a smile. "Essentially it will allow your body to adjust as needed to any circumstances. As you heard, I'll have to confirm it worked before we board the ship."
You nod in confirmation of your understanding. Without further word, the alien cow woman gently presses the needle into your neck. Your vision gets cloudy for a moment and your legs feel very unsteady, but Taura supports you until you adjust, can stand in your own, and your vision has cleared.
You look at your host for the next month and realize something is off. She was now nude from the waist down! When did she pull off her pants?!
Taura smiles, "Ready for that test?" she asks, bending at the waist and shaking her round ass in your face.
You try to stammer a response, but none comes. Without waiting for further confirmation, she launches herself up and backwards, landing her soft ass directly on your much smaller body. You flatten instantly any groan in pain as Taura shifts and moos happily on top of you. After a few painful moments, she stands to her feet and watches happily as your body restores itself.
"Test 1 complete!" she smiles.
"TEST ONE!?!" you yell. "How many tests are there and why the hell did you flatten me!?"
With her smile still plastered to her face, Taura responds casually. "There's just one more test. And how else do you expect me to confirm that A22 worked?"
The logic was...relatively sound, but you were not happy. Before you could protest further, Taura bent over again, this time gripping her cheeks and exposing her large crack.
"Now for test 2. Get in." she said casually.
"What? No, you cannot seriously expect me to just walk myself into your ass," you protested.
Taura stood and shrugged. "Why not? You're the right size and it's a perfect way to test your ability to function with limited oxygen. Unless you'd like to try a more cramped space on for size," she said excitedly, her hand moving to her crotch. You recall what Taura said earlier about her species being more hands on. She wasn't exaggerating!
"N....no, you're right. Your ass makes perfect sense," you relent.
Her smile returning, the cow again exposes her massive crack to you. You move slowly and hesitantly towards her, but Taura is impatient and grabs you by the collar, her strong arm forcing you between her cheeks.
With a satisfied sigh, she stands, clenched her cheeks, and pulls up her pants. Sealing you completely.
"I suppose I could have just covered his mouth and pinched his nose, but this is soooo much better," she says quietly to herself while enjoying your squirms.
After a few minutes, confirming that you had not passed out from lack of air, Taura announces that you've passed both tests. The serum worked and you can safely board her ship. But does she let you out of her ass first?