When you spell it like that, it just classes it right up. "I'm eatin' mah roughage" sounds so coarse. But you're like "I am consuming mon fibres, s'il vous plaît."
(No, I won’t go into a discussion how language changes and things that used to be mistakes are no fine and yaddayadda. In today’s standard English you cannot contract ‘I have’ if ‘have’ is not an auxiliary verb.)
Note that the have verb is not contracted in writing when it is the main verb in a sentence and means “to possess.”
Do toilet poltergeists stalk you and turn normal chairs into toilets, like in those commercials? Or are those, like, not an entirely accurate depiction of the condition?