Hot Summer Job/Search through her dresser
You navigate some of your sister's "art" in front of her dresser and pull open her drawers. These, like everything else are a mess. It looks like entire laundry baskets just get dumped in here. Shaking your head, you do some simple sorting and folding, almost forgetting that your plan involved snooping.
The first item of interest you come across is a bikini. Bree has always been a one piece girl, so it's a bit odd to find a two piece, let alone a bikini. But it is a full blown bikini, side-ties and all. It seems like there's an awful lot of "string" and less "bikini" than even something mom would wear. But presumably mom allowed her to buy it, so maybe it's not as small as you think it is.
The next drawer down you find a pair of panties buried in the back, which would not be strange to find in a girl's dresser. But they're not in her pantie drawer, and these panties are "less" than panties... Bree has a thong.
Now that is something you're sure mom would not let her buy. So how did she get these? The narrow crotch has horizontal rainbow stripes running across it. The waistband is little more than a half inch black band of elastic. When you turn it around there is even less fabric than the front, a colorful triangular patch of fabric the only thing connecting the waistband to the thin strip designed to slip between her cheeks.
For some reason you start picturing your sister wearing this thong. Only the thong. It sends butterflies through your stomach and into your dick. You quickly shove the pint-size lingerie far back into her drawer and do a quick and sloppy cleanup of what's left.