It’s trivial, but I can’t help it. It bugs me when people who want to draw out a word for emphasis arbitrarily type a string of consonants at the end instead of a string of vowels in the middle. For example, one might reasonably shout, “Yessss!” but certainly not, “That dude was fasttttt.” Way cool = “cooool,” not “coollllll.”
I realize this poses a problem with short vowel sounds in a word like hot: “hooooot” may look like something an owl says, but I would argue that “hottttttt” is certainly not better, based on the amount of spitting required to render it audible. And how can you expect people to believe that “me n my girls r gonna have funnnnnnnnn tonite” when string of nnnnns reads like a soft snore?
I propose no rules other than to make what you type accurately reflect the sounds you would expect someone to make when they say it. Perhaps, “It is ho-o-ot outside!” Or better still, “It’s scorching!”