Hot Summer Job/Make Bree put on her skimpiest underwear
Your sister's smirk grows bigger as you stare her down, anticipation building around what her next dare might be. You know what you want, but you don't want to blurt it out either. There still isn't a good indicator for where her line is, so you try to act a bit playful instead.
"So... you're not wearing any underwear right now, are you?"
That's no secret at this point, but Bree is still embarrassed by the question. Her expression turns to guilty affirmation as she looks around the room slyly. She slowly shakes her head, a silly grin taking hold.
"We should fix that. Your dare is to for you to be in your underwear for the rest of the night." You pause, wondering if you can take it a bit further to make it bullet-proof. Bree is still looking away with a slight smile, one finger picking at the couch. "And it has to be your most revealing; the sexiest thing you own."
Bree is already starting to blush. Head down, she lifts her eyes to steal a glance at you then looks away again. "Really? For the whole night?"
"If I have to wear a bikini to bed then hell yes all night!"
Your sis lets loose a short giggle, unable to contain her amusement. She steps away from the couch slowly and carefully, then bursts into a run as if you were chasing her away. You wait not-so-patiently downstairs, checking your phone over and over for a text you never receive. It's almost 6 minutes later when she finally comes back from her room, no different than she left.
"Why didn't you change?"
She hops to a stop in the middle of the room. "I did! I put on underwear. See?"
Bree partially lifts her skirt, just enough to prove there is a garment of some type being worn beneath it. If that's all she did while up there she must have gotten lost along the way since she was gone for quite a while.
"No, no, no. The dare was for you to only wear underwear. It's hardly daring to wear panties with a skirt."
Bree gives you a look of insincere surprise. She had to know what you were asking. In fact, that's probably what took her so long, mulling over how to mess with you. She can't even keep her lips from curling upwards as she expresses her "shock" about this.
"I didn't know that! I thought it was a weird one. I screwed up your dare, huh?"
You raise an eyebrow. "I guess. It's not exactly hard to fix."
Bree sighs. "Yeah, you're right." She sticks both her arms up into the air, looking at you expectantly.
"What?" you ask, a tad confused.
Bree does her best to positively ooze bashful innocence, swaying her hips and shaking out her skirt. "Don't you need to undress me?"
Your other eyebrow joins your first. This you were not expecting. Your sis is blushing pretty hard now, no doubt straining to drum up every ounce of courage to go through with this veiled request.
"Yeah, I suppose I could do that. Only because you screwed up the dare, right?"
Bree smiles through her embarrassment and nods knowingly. You stare across at her wondering just how much she must want this to gift it to you so plainly. Maybe she just couldn't do this dare on her own and this helps to disconnect her actions from what she's agreed to. Or maybe she's fantasized about having a boy strip off all her clothes, even if it's her brother. Whatever the case, you're happy to accommodate her.
You step forward and quickly peel Bree's shirt from her torso. She bashfully beams once her head is free and she can see you staring down at her real surprise.
"Do you like it?"
Your little sister does not and never has - that you know of at least - worn a bra. This hardly counts. The thin white cotton underthing has no real shape, other than a downward dip in the center of her chest where cleavage would normally be found. But this is no bra. It's a crop top tank, a tube top with straps, a cover to conceal what isn't there. The little bit of lace edging and a tiny fabric bow in the center are the only indications that this horizontal band of fabric is supposed to be some sort of bralette and not an absurdly short top. You can't imagine the flimsy and shapeless article would be able to support anything if your sis needed it to.
And yet, despite how frustrating it is to find it there, this top is doing a fantastic job of highlighting your sister's excited pink nipples as they poke against the thin contrasting fabric.
"Oh! Uh, yeah, that's new," you comment, already moving to undo her skirt.
"Mom bought a bunch for me but I don't really like them. But since you're dared me to..." she trails off, mostly because you just pulled her skirt down off her hips to reveal her second surprise; a thong.
You can't even pry your eyes away when you ask your sis, "Did mom buy you this too?"
"No... Mara's big sister bought it for me. I didn't ask for it, not really, but Mara said it was my fault. All I said was her sister's panties were pretty and so Mara dared me to wear them but I would only do it if did too so we tried some on but then Naomi caught us and she took us out and bought one for both of us and told us not to tell mom."
Bree's cheeks rosy up again as she ramblingly informs you of how she stumbled into ownership of a genuine pair of thong panties. Of course you can hardly believe it even exists, let alone is now being worn in front of you. The rainbow striped crotch, the thin black waistband, the narrowness of the fabric, all of it in stark contrast to traditional full-bottomed panties and working to expose that much more of her body; not the least of which is a sultry diagonal V where her hips join with her pelvis. You didn't even know they made stuff like this for pre-tweens.
"Um, don't tell mom, 'kay?"
Bree drops her hands in front of her crotch with a slightly concerned look. It seems to be the result of her anxious state taking in your shocked expression and causing her to worry. Of course you're not going to tell mom. You've done stupider things, but never on purpose. But maybe it's better if Bree thinks you might tell on her.