Your woman's intuition was telling you not to cover up Reisen's creepy obsession, but your man's intuition was telling her to shut up and get back in the kitchen. She kinda disgusted you last night, but you still had a soft sport for the crazy bunny girl.
"She was rubbing off to a pi-OOPH!!" you grabbed Tewi and covered her mouth before she blurted out Reisen's secret.

"Eh..." you did some quick thinking, "Reisen was taking me on a boat ride last night before we ran into that creepy samurai... and... got a little seasick." Reisen turned her head to you in a questionable manner. Weird thoughts of her defiling her love-pillow flashed in your mind as you tried to keep up the charade, "I kinda had to hold her eyes while she ralphed over the side of the boat." Surely puking in front of your victim-er-CRUSH is a lot less embarrassing than stockpiling life-size dolls of your crush and schlicking over her to a pillow, right?

"Oh dear," Eirin sighed, "Reisen, I told you a thousand times, youre on medication. You cant handle boat rides while youre taking your migraine medicine. They make you nauseous."
"Taking that nasty medicine makes me nauseous," you heard Reisen mutter.
"What was that?"
"NOTHING!" Reisen quickly blurts out, "W-which reminds me! It's time for my morning dose!" She pulled out a little medicine bottle in front of Eirin and picked up her spoon, poured her medicine in the spoon, and sipped it.
The poor bunny girl's face went blue, trying to keep straight in front of the doc. She was squinting her eyes and mouth and her bunny ears twitched about like crazy. Geez, was her medicine really THAT bad?

"Ms. Yagokoro," another bunny girl came out of the doorway and stepped toward Eirin, "youre 9am patient has arrived."
"Ah! The girl about the breast reduction!" Eirin stated... then for some reason her eyes widened as she repeated, "breast... reduction..." then she stared down at her chest... then over at you, "...I'll... be right there." and headed off with the other bunny girl.

"What's with Eirin?" Tewi asked.
You wanted to say 'She's still bitter about 2 nights ago' but you werent stupid. Actually, you're being WAY too soft on Reisen, so you probably are.

"PST!!" speaking of, your medicated stalker spit out the awful medicine and chugged down her glass of water to wash the taste out of her mouth! "Ugh... sometimes I think Eirin was born without tastebuds!"
"Speaking of strange tastes," Tewi put on a very cocky smile, "was it good for your pillow as it was for you?"

"!!" Reisen's red eyes went small and her eyes stuck up in the air, "...wh... what are you talking about?"
"Aw c'mon! No use denying it, Little Miss Lovesick! Me and Alex saw the whole thing," Tewi turned to you and smile, "didnt we, Alex-sama?"
This would make wicked blackmail... but then again, you remember being in Reisen's shoes after being degraded to wearing those stupid dresses Big T made you wear! None of the Yakuzas let you live that down.

"I have no idea what youre talking about," you replied with a straight face, "I was in my room the whole time."
That made Tewi big smile immediately fade in an instant! "Wh-what?! No you werent! You were with me in Reisen's room! You saw what she did!" Reisen looked over you, shivering and sweating.
"What did she do?" you played stupid.
"Will you cut that out?!" Tewi started to get angry, "you saw everything! You even saw what was in her closet!!" Yep... the dolls!

"Tewi, it's not making up sick stories to demoralize your co-workers," you lectured her which made Tewi even more mad!
"ALRIGHT, THAT'S IT! I'll refresh your memory! Let's take a look at the film..." Tewi reached into her pocket. Then her other pocket. Then her other pocket. Then she began to panic and pat herself down, "Wh... where's my camera? Hey, where is it?! Dont tell me I lost it! It cost me 800 friggin Lunar dollars!! Urrggh!!!" And with that, she ran out of the room looking for it.
Little did she know, you swiped it from her while you were making that excuse to Eirin! A little trick your old employer taught you.

And sure enough, Reisen sighed in relief... and set the butcher knife that she hid behind her back back on the table. Holy crap, did you just save Tewi's life?! Your woman's intuition has just kicked your man's intuition right in the balls!
Perhaps you shouldve told Eirin what you saw. You know what's gonna end up happening next: Your dad's gonna end up in the hospital with a broken leg, your cat's gonna be found in the microwave, the words 'REISEN+ALEX4EVER' will be painted on your driveway in blood, then youre gonna wake up in a dark room with pictures of your all over the place, tied to a chair and force fed carrots for the rest of your short life!

Oh puh-lease! Now youre just exaggerating things! ...Then again, how did Ms. Inaba manage to get a personalized love-pillow with your picture on it in such short time?
Speaking of which, during the whole time you were reflection, you noticed in the corner of your eye that Reisen was giving you a closed-eye smile while tilting her head the whole time.
"Uh.... so...." you took a deep breath, "guess we better start manning the shop then, huh?"
"Shop's closed today," Reisen still smiled, "it's Sunday." The medicine shops closed on Sundays. Great.
"Oh. Well, um... I guess I'll just take a walk around to pass the time. See you later, Re-"

"Wait!" Damnit, she grabbed your arm! Damnit, she's even stronger than you! "You'll need a suitable guide to guide you around! I'll volunteer! I know the best places!"
"Thanks, but I'd rather be surprised," you assure her and struggle to pry her hand off you. But she aint letting you go!
"Surprised?! Then I know the PERFECT place to be surprised!"
"Oh? And where would that be?"
"Now now!" she waved her finger and winked, "if I tell you, it wouldnt be a surprise! I'll show you-"
"You know what? On second thought I hate surprises! I'll just sit in my room for a while!"
"Can I join you?"
"No, I want to be alone... to clear my head."
"I know the PERFECT way to clear your head!" Good lord, this woman wont give up!

THANKFULLY you finally pried hand off you!
"Anyways, I'll be going now!"
"But you cant," Reisen calmly and surely assures you.
"Why not?" you asked with curiosity... and fear.
"Because there's a slight tear in your shirt that needs to be stitched up."
"What tear?" you looked on your shirt it... failing to notice the eerie twinkle in Reisen's big red eyes! Eerily dilated big red eyes!

"THAT ONE!"
*RRRIIIIPPP!!!* One second later, your shirt's completely torn to shreds! Once again, youre shirtless. Youre also topless. Your bra magically vanished, too!

"WH-WHAT IN THE-"
Reisen flashed a grin, "Oh my! Talk about a wardrobe malfunction!" How did she-oh right. You put your hand over your boobs, desperately trying to cover them up as her 'casually carefree' smile started to drool! It's pretty obvious what's gonna happen. Either Shiro's migraine pills arent doing a damn thing, or theyre working TOO well.

"Reisen... dont even think about it."
"TOO LATE! NYAAAA!!!" before you could blink, Reisen leaped at you!

*BANG!*

"EEEKKKK!!!" and before you could blink again, Reisen shrieked and started to clinging to your body, shivering in fear! Man, that little fearless 'IMMARAEPU' phase sure went away awful quick! Tsk... all bark and no bite.

Wait a second! That was a gunshot you just heard! Somebody tried to shoot you... or her. As your bunny friend went from yandere love-sick stalker to scared little girl clinging to her big sis (technically, LITTLE sis. She is older than you after all), you peeked through the window for the shooter, but he/she was already gone.

"I-I-i-i-is it gone, Alex-sama?" Reisen whimpered, still clinging to you for dear life.
"I uh... think so," you asnwer, "you can let go of me, now."
Unfortunately, she shook her head, "N-n-nuh uh! If that's a youkai hunter, I aint leaving you alone with him!" Even while scared stiff, she's still awful stubborn. Oh well. "Oh god! What if he's after the rabbits?! What if they found out about the bounty?!

"Alright, dont panic" you tell her, "let's go warn the others."
"A-A-actually, as the big sister of the group, it should be my responsibility... to... tell the others," Reisen failed at pretending to be brave, "my fellow rabbit sisters look up to me for inspiration. Caring for their well-being is my job!"

"Youre still shaken up," you tell her, "plus I've dealt with these kind of people a lot. I'll handle this."

"N-NO!" she rejected, "Youre still the new girl. Y...you should take refuge until I come back... p...preferably in my bedroom, where it's safe..." Uh, it looks like she's starting to get over her fear, "between my nice warm sheets... getting your beautiful body nice and warm... wrapping my lucky blanket around your wonderful naked peaking bosom... while my lucky mattress gets the pleasure of warmth from your nice round bottom-"
"OK OK!! I GET IT! SHUT UP!" you couldnt bear to hear any more!

She seems rather intent on handling this herself for some reason. Sounds like this aint the first time she's been in this situation. Since she obviously has more experience, maybe you should let her handle things.
Then again, she's STILL trembling on your leg! (at least you HOPE that's just trembling!)