"Yǎng yang" is a reduplicated form of the noun "yǎng" (itch), used to express a mild, tingling, or playful itch—often one that’s not serious or painful, but rather ticklish or slightly irritating. The repetition softens the intensity and adds a colloquial, sometimes affectionate or childlike tone. It’s commonly used when describing sensations on the skin, especially in informal speech or when talking to children.

This word reflects a broader pattern in Chinese where reduplication conveys diminution, familiarity, or gentleness (e.g., 看看 kàn kan 'take a quick look'). While 痒 alone can refer to medical or uncomfortable itching, 痒痒 shifts focus toward light physical sensation—like the feeling of a feather brushing your arm, an insect crawling lightly, or even the playful urge to scratch after hearing someone describe it. It’s rarely used in formal or clinical contexts.