Good job Lara, starting to catch up.
This is a one joke sketch that probably should have been 45 seconds, but somehow the director pushed it to being near 2 minutes. How did this happen? Silence. Now, I love silence and think that the use of it in this sketch makes this a better sketch, but I think that it is also a selfish act. Sure, it makes the sketch better, but it also paces the entire show differently – it forces a stop in the action where the action should just continue to the punch line. The process of a misunderstanding is funny though and the payoff of a phrase that doesn't make sense and is gross is a good payoff. The even better payoff is that both actors act so unoffended by the realization of the truth and just slightly weirded out. Cora's pauses throughout seem drawn out and forced and then her last pause (the one that could have been drawn out for a while) is forced in before the laughter dies. Ben, on the other hand, pauses for the perfect amount of time, but has this strange desire to close his eyes to show confusion or awkwardness – it only serves to look like he's telegraphing his emotions.
A great payoff and solid acting, but the sketch should have gone quicker and had the awkwardness propel the action as opposed to stop it.