Surgically lengthen your quad muscles so squatting is the only option.
Replace all your furniture with exercise balls and then feel too self conscious to actually sit on them.
Casually scatter spikes on all your chairs.
Eat so many chili flakes that the intense and constant burning in your intestines requires you stay upright.
Pretend your glute muscles are war criminals and all chairs comprise a human rights tribunal.
Devote years to circus training and then swallow a rod that goes from the back of your throat down to the base of your spinal cord.
Have someone train you as a dog, and then never give you the “sit and stay” command.
While standing, go to medical school, find a lab willing to support your research, become excellent at writing grants, get affiliated with a university, get divorced because of your overwhelming devotion to work, and eventually find the cure for intestinal cancer so you can sit all you want.