Five, no

You tap five times as quickly as you can, hoping for some respite from the pain currently being inflicted on your defenseless balls.

"Very good, my ****."

You prepare to take a breath of air quickly, but Mistress Jessica dashes your hopes as she continues speaking.

"Guessing wrong like that saves me the trouble of having to move from my seat."

Laughing good-naturedly, Mistress Jessica relaxes with the full weight of her ass on your face while you try not to squirm from the pain of the clothespins. The lack of air slowly shifts from being a minor concern to at least as important as the pain of the clothespins, at which point, you're relieved to hear Mistress Jessica inform you:

"Here's your next chance for a breath, my seat...the next one could be a while."

You focus completely on the aching pain in your balls, determined to catch how many clothespins she adds. Your concentration pays off, and Mistress Jessica does nothing to throw you off, so you can tell for certain that she added exactly two clothespins...

As you prepare to tap out your answer though, a problem arises. You don't know how many was the right number the first time...it's two more than "not five", so it can't be seven. But aside from that, you're stuck with a guess yet again.