When a tattoo itches, this is typically due to the tattoo healing process. As the skin heals, it can cause the sensation of mild itching or irritation. During the healing process, it is important to avoid scratching the tattoo, as this can cause damage to the skin and can interfere with the healing process. It is best to follow the aftercare instructions from the artist and to keep the area clean and moisturized. If the itching becomes too intense, consult a medical professional for advice.