Carol's not timing them and she doesn't have any kind of internal timer power that would make her take note. What she does note is how good he feels and the sensations that he's coaxing out of her body.

Carol keeps up with him as long as he does and could probably go longer. But she's thankful that when he murmurs about getting close that she's close as well.

"Me too," she murmurs back before pressing a kiss to his jaw. She's on birth control and her body can fight off most diseases so she's really not worried about any unwanted outcome.