Be circumspect.

You close out of Shelly's computer, returning everything to exactly as you found it when you entered. She'd flip out if she knew you entered her room without permission, especially if she knows you'd discovered her secret files. The irony isn't lost on you, of course, that she has no problem barging into your room.

When you get down to the living room, the only room with enough open space for her yoga, you pause at the entrance and take a peek at your sister. She's wearing black stretch pants, made of fabric that's specifically designed to mold to her body and even you have to admit, her lower half looks fucking fantastic. Long, toned legs and a tight ass that is only found in the young. Her butt cheeks flex beneath the surface as she holds her current pose, exhibiting an amount of control that draws your mind down a naughty path that you might have to explore in future dreams.

But as magnificent as her ass is, her top is even more amazing. Shelly's large tits--a bit bigger than yesterday, thanks to your unknowing intervention--are barely contained underneath the ill-fitting sports bra she's borrowed from your mom. Your mom's bust is a little bit bigger than your sister's and they don't hold her mounds in place nearly as well as they should. Beneath the top, Shelly's breasts slide and wiggle and jiggle, their motion a constant delight to your eyes as you drink in her sexy body. As you watch she shifts her pose, moving to a forward bend which leaves her sweet udders hanging down, blocked only by her long ponytail which swings back and forth gently. The neckline on the sports bra is loose and you can see a great expanse of what it's supposed to be hiding, all smooth skin and soft curves. She dips a little further and you cock rockets to attention when one of her swollen nipples pops into view, hard from the friction of rubbing against the fabric.

A big part of your minds screams, FUCK YEAH! But there's another part, one that you can't quite ignore that raises an issue. A few days ago, I never would have looked at Shelly like a sexual object...or my mom for that matter. But now I'm ogling her like a fine cut of meat and imagining all the dirty things I'd like to do to her body. Have I always been this perverted or are the dreams changing me as much as the others? Maybe Shelly's love of porn is....

"This isn't a free show, numbnuts," you sister says, interrupting your thoughts. Still in the same position, she's looking at you with scorn on her face but you're beginning to wonder how much of that is an act. She has to know her boobs are on full display. "Stop staring like an idiot and go somewhere else."

Time to initiate your plan.

"Sorry," you say. "I'd just heard you talking to mom earlier about how you needed to buy some new yoga stuff. I was planning on stopping by the mall today myself and was wondering if you wanted a ride or something?"

You see a moment of wariness flit across her face. It's not often that either of you do something nice for the other out of the goodness of your heart, your relationship has always been a bit more competitive and antagonistic. It disappears almost as soon as you see it, then she straightens up, her breasts bouncing nicely, and nods her head. "Sure, that sounds good, actually. Give me half an hour to finish up and shower, and we can go after that. Ok?"

"Sure," you agree and back away, making sure she can't see the hardon you're sporting. That should give you just enough time to rub one out and get changed.

***************************************************************************************

Thirty-five minutes later, the two of you are in the car, heading to the mall. Your sister has changed into a pair of white short-shorts and matching blouse, with the top four buttons undone. You can't help but sneak glances at her as you drive, drawn to her incredible cleavage. Shelly has her window rolled down and is leaning against the opening with one arm, her blonde hair, now unbound, streaking behind her like pale strands of light.

It's a comfortable silence that you travel in for the first ten minutes or so. You spend much of the time considering how to approach Shelly without having her shut down. You finally decide that a blunt approach might elicit the best response.

"I had a dream about you last night."

Your sister's head whips around faster than you can blink, her eyes wide and mouth forming a shocked 'O.' You almost have to laugh as you can almost see the thoughts racing through her head. "What...uhm...what was it about?" she finally manages to say.

You pretend to ignore her distress and shrug. "Oh, I don't really know," you lie. "I remember it being a little weird, but also really nice at the same time. You were there and I was there, and we were in my room and you were helping me with something important. The details are kinda fuzzy though. You know how dreams can be."

Shelly's light skin--she avoids the sun like the plague--turns even paler as you outline the barest parts of your shared dream, her thoughts obviously going back to what she was wearing, how she was acting and how big of a dick you'd had. Her thighs tighten as you speak and her breathing stops.

"Do you remember your dreams?" you ask.

It takes her almost a full minute to cobble together a reply, her face now deepening into a lovely fuchsia. "Sometimes. I mean, not all the time but I think I remember part of my dream from last night too. I think...uhm...I think you might have been in my dream too. I...enjoyed it." She says it fast, almost like a confession, clasping her hands in her lap. She's not looking directly at you, her head looking down, but you can't help but sense she's hesitantly waiting for your reaction.

"Dreams are funny that way, aren't they," you laugh. You gently elbow her shoulder and she finally looks up at you. You wink at her. "Maybe we should share our dreams more often."

She blushes but grins back at you. From there, the dam breaks and some of the walls that had been built between the two of you--normal edifices that arise between siblings--begin to crack and crumble. For the rest of the drive, the two of you talk and connect on a variety of topics. You tell her about school and the courses you're taking, she tells you about the perils of high school and her troubles with her last boyfriend--you don't press her too hard about this subject but your heart skips a beat when she cryptically remarks that he always left her 'unfulfilled.' It's the best conversation you've had with Shelly in years.

By the time you reach the mall, the two of you are laughing and genuinely enjoying each other's company. You park near the sporting goods store and walk in, still talking. Shelly finds a group of bras that she thinks will work and heads to the changing rooms, which are tucked in one corner of the store. If this was a dream world, you'd push Shelly to need your help in choosing the write bra, perhaps modelling each one for your discerning eyes, maybe even calling you into the tight, cramped spaces of the fitting room to allow you to be more hands-on with the fitting; but this is the real world and you have no special powers here.

Shelly finds a couple of replacements and pulls out a card to pay for them. You don't get a good look at it before she's got it back in her purse, but you could have sworn it was your father's credit card. How'd she get that?

As you head for the exit, Shelly grabs your sleeve and pulls you into the main part of the mall. "Where are we going?" you ask as she leads down a small branch, away from the main arteries.

"I don't only need new yoga clothes," she tells you with a grimace. "None of my regular bras are fitting well either, so I have to get a few more of those too."

Soon you're standing outside the pinkest store you've ever seen, with all variety of lingerie, underwear and swimsuits on display on mannequins and hanging from racks. Not exactly the sort of store a guy goes to with his sister. But Shelly just drags you in without giving you time to protest

"Welcome," a saleswoman says we you enter. "How can I help you?"

You do a double-take. Standing in front of you is the redhead you mercilessly fucked in front of a crowd during your daydream yesterday. She's wearing a tight-fitting pink top--which, to be honest, clashes with her lovely hair--that has a subtle v-cut set in just the right place to showcase her gigantic bosom and lengthy cleavage; a nametag with 'Jean' printed across it lies at the peak of those pillowy mountains. A white skirt, hanging to just above her knees, completes her uniform.

Jean also does a slight double-take when she sees you, but recovers quickly and returns to service mode.

"Hi," Shelly greets her. "I've...added a little bit up top recently and I need to figure out what my new size is. Can you do a fitting for me?"

"No problem," Jean says with a smile. God, you could listen to her Irish accent all day. "Us busty gals got to stick together. It's not easy finding undergarments that fit properly when you're packing as much as we are upstairs." She nods to her ample chest and the two of them burst out laughing in sympathetic unison.

Jean takes your sister by the hand and soon the two of them are talking and giggling like they've been best friends forever, comparing horror stories about poor quality bras and complaining about how they're always bumping into things with their big boobs. Jean raises a rosy eyebrow when Shelly introduces you as her brother, and informs your sister that the two of you are actually in the same college course, making Shelly shake her head at the coincidence. Finally they move on to examining the newest designs they'd just gotten into the store.

Once again you are left behind as they go into the back room for the official fitting and cup assessment, but this time your imagination runs wild with two hot girls instead of just one. Maybe Jean has to take off her clothes to show your sister how much she loves her own bra; maybe Shelly will will discover her sapphic side during the fitting and be aroused by Jean's soft caresses; maybe they will invite you back to do a comparison of their juggs, judging them for softness, taste and best titfuck; maybe they'll decide they need to do a cock measuring too, to make sure your pants are fitting the way they should. By the time the two girls return from the back room, you've run at least a dozen scenarios through your imagination and are caught with a line of drool running from the corner of your mouth, making the girls twitter together again.

Shelly swipes your dad's card one more time, thanks Jean for her help and accepts a card with Jean's number on it in case she needs any more help or just wants to talk. You head back to the car and head for home, having spent a pleasant afternoon with your only sibling. You may not have learned a great deal more about your dreams, but you still would consider this trip a resounding success.

Until your sister asks you a question that makes your stomach drop.

She looks at you with a serious expression on her face. "Why didn't you buy anything while we were at the mall?"