I'm going to ask my roommate to clean the bathroom
Why do you need to tell them to clean it?
Because, I'm tired of cleaning it everyday.
I think it might be helpful you make a house chore list so everyone knows what part they need to do. I don't think it is fair for you to only clean up the bathroom if someone else makes it a mess.
I'm going to make him pay the price if he doesn't help me clean the bathroom.
It is ok to want people to pick up after themselves. I think most people would assume roommates split the rent fairly in a 50/50.