If he makes a correct 4th down decision, it will be the first one.

Removing the comma would change the meaning of the sentence in a way that would be nonsensical in this context. It would mean ‘You do it at that particular time’. As written, it means ’You do it, in that case’, which is correct. What is the penalty for an incorrect grammar Nazi comment?

So, sex then.

That game was like sex, if sex included Al Michaels and Chris Collinsworth watching you the whole time and getting completely flabbergasted by what they were seeing.