"You shouldn't," she whispers, her voice barely audible as her best friend's boyfriend traces the curve of her breast, his thumb brushing against her nipple. His eyes meet hers, a challenge in his gaze as he leans in, flicking his tongue over the hardening peak. She bites her lip, stifling a moan, as he continues his tantalizing exploration, her body betraying her as her nipple stiffens under his expert touch. The forbidden fruit tastes sweeter, and they're both craving the next bite.