In Caribbean English and dancehall culture, to 'whine' (or 'wine') means to dance with a slow, fluid rolling movement of the hips. It is a positive, celebratory term and is the core movement of soca and dancehall. Outside that context, 'whine' has its standard English sense of complaining. If your teen uses it, it almost certainly relates to dance moves they have seen on TikTok or in music videos rather than the dictionary sense. It is not inherently sexual, though dancehall culture is sometimes provocative — the word itself is just the movement.