It sounds like you're looking for a guide on how to take a great photo featuring a pink thong, or perhaps you're looking for advice on styling and photography within that specific aesthetic.
Not all pinks are created equal. The shade can change the entire "vibe" of the photo: gay pink thong pic
Softer, more "innocent" or loungewear-focused. Works great with natural morning light. It sounds like you're looking for a guide
Sit on the edge of a bed or chair, leaning back on your hands. This elongates the torso and keeps the focus on the waistline. consider these styling tips:
To make the photo more dynamic than just a standard selfie, consider these styling tips: