What is why are my thighs so big when i sit?

As an AI language model, I do not have access to your specific physical details or medical history. However, there could be various reasons why your thighs appear bigger when you sit, such as:

1. Excess Fat: Sitting for prolonged periods without enough physical activity causes the fat tissues to accumulate in the thigh area, leading to an increase in the width of your thighs.

2. Poor Posture: Sitting with poor posture, or hunching over, can push your thighs towards each other, which can make them appear bigger.

3. Water Retention: Sitting for long periods can cause fluid retention in your legs, leading to puffiness and an increase in size, especially during the menstrual cycle.

4. Genetics: Some people may have a natural genetic tendency to store more fat in certain areas, such as the thigh and hips.

Overall, lifestyle factors such as diet, exercise, and sitting habits can play a role in the size of your thighs. If you are concerned about the appearance of your thighs or any other health issues, it is advisable to consult a medical professional for personalized advice.