Forcing yourself to do whatever you don't want to do is dumb. You are a smart individual, not cattle. You can pitch whatever you need to do to yourself. You can make yourself want it. And if you can't, then you need to learn communication. Never force yourself to do whatever you hate. Drop this dumb discipline stuff. Be smarter!
Discussion
You can't apply this advice to hard things in fact this advice In general will lead to comfort seeking which in itself is a problem.
I am doing the hardest things humans are capable of doing... Fast for 21 days lifting in the gym every day and walking 10k steps minimum... Going on 5 day hikes in remote mountains without food and equipment, where at night is freezing... Learning new skills, cold aproaching women on the street... Doing all kinds of very hard impossible stuff. Never ever I fell into comfort seeking. I hate comfort. Whatever ai do is always hard and I always pitch it to myself and do it because it's interesting and I want it. If you are a boy who is pleasureseeking, grow up. Men are conquering the world, willingly 😉