You want to buy some panties for your girlfriend, so you ask it I’d help you choose some. You don’t know much about panty styles and, well, would I mind showing you some? I eagerly agree, even offering to model them and take some pictures for you. Seeing me try on all those panties—thongs, hipsters, bikini cut—in all those fabrics—cotton, satin, net—gets you incredibly horny. You’re a little worried about hiding it, but I don’t seem to mind. Because I have plans for you: I know all about your diaper fetish. I mean, I’m your sister. How could I not know? And you know what? I like it. I’m the yin to your yang, bro, and I’ve decided to make you my personal panty fetishist. Your allowance is going to buy me more sexy panties and you’re going to be spending all of your free time worshipping them. You can start right now by jerking off for me and cumming all over my panties! You’re welcome for the help. After all, what’s a sister for?