Thrillist Evolve Intimates

This lingerie brand has a fully interactive design studio that'll guide you through building custom unmentionables from g-strings and thongs, to bras and "chemises" start-to-finish, letting you choose from various base fabric types and colors, trim options (satin stretch, braided, etc), and an "applique" like a mini bow or ribbon accent; they'll also ship gift cards so she can design her own, a safer route than you just ballparking she's an XL.