Is it possible to shiver on purpose?

Yes, it is possible to shiver on purpose. Shivering is a natural reflex that occurs when the body tries to warm itself up. When the body is exposed to cold, the blood vessels constrict and the muscles start to contract and relax rapidly, which generates heat and helps to raise the body temperature. By consciously tensing and relaxing specific muscle groups, it is possible to induce a shivering response and generate heat, even without being exposed to cold temperatures.