"Office chair butt" is a nickname for the sore, stiff, or numb feeling in the buttocks and thighs caused by prolonged sitting. While not a medical term, it is a common experience for those who sit for long hours. The condition results from constant pressure and a lack of movement. https://www.sweetcrispy.com/blogs/news/what-is-office-chair-butt-causes-symptoms-prevention-tips