Yes, the button on the lid pops for the first time when the seal is broken. If you’re not sure if something has been opened before, you can look for the raised bump on the lid, or press the center of the lid to see if it makes a popping sound.
I’m not sure what that has to do with the strip you linked to though. Well, I have one explanation, but it seems like a stretch.
I believe the OP is talking about this cartoon:
(this one is referring to the man-preserve’s outrage that his supposedly-virginal newlywed wife-preserve has in fact already been ‘opened’ - as indicated by the pop thing in the lid being able to pop before he tries to open it)
…I must preview, I must preview… Yes, the Preserves thing is what I was going to link to. Instead, I linked to Hard Read because I wasn’t paying attention. I think that has to do with the CliffsNotes that are on the desk of the male book character.
Ah, so it is. I somehow saw that as him unscrewing (hehhehheh) the lid of the female character and it popping and that making him outraged, but now that I look more closely, he’s not holding on to the lid.
The CliffsNotes thing: In the first panel, the female book says that the male is the only one who understands her. In the second panel, she spots the CliffsNotes on his desk; obviously, he doesn’t read her like a book, he’s read the abridged version. All his insights on her are from the CliffsNotes. So sad.
Well then, what’s the popping sound about? Taken literally, the text on the cap says that the button will pop if seal is broken, not when seal is broken, so the popping sound indicates a broken seal.
The popping sound happens when it is opened the first time, as the OP suggests. I understand the confusion, as the button only pops the one time. If it pops on the wedding night, what is the complaint?
If you take an unopened jar of baby food, the center of the metal lid is held down by the vacuum, and pressing it does nothing. When you open the jar, you get a sucking sound. If you then put the lid back on, the center of the lid is now raised, and if you press on it and let go, you get a soft popping sound. It’s more of a double pop, once when you press it, once when you release. I think it’s the sound of the metal flexing, not air - you can get it to happen even if the lid is separated from the jar. From his hand position, I’d guess he pressed down on her lid and heard the pop.
The wording is ambiguous - it should say ‘button will pop if seal has already been broken’ (because that’s what actually happens in reality) - it pops spontaneously when you open the jar and makes a popping sound every time it is pressed thereafter.
If you look closely at the first panel, the female book has her foot between the male’s legs, as if she’s using it to feel his package. In the second panel, the Cliff’s Notes appear to be falling out of his pants. I took that to mean that he had it shoved in there to falsely enhance his, erm, bookhood. This fits with the strip’s title, “Hard Read”.
Of course, the “You’re the only one who understands me” could be a euphemism for “You’ve got the biggest one ever!”