Something cute that'll push them up and make you stare, obviously.

[Men should be forced to take a class on these sorts of things.]

If you show up with a nice gift she'll probably let you be especially awful.

[If nothing else she could teach her brother how to properly utilize a girl's frustration without getting something bitten off.] Let's go look.

[And in the meantime she could just wear the black lace bra with it's unhelpful little cutout portion.]