This phrase is very difficult to interpret without more context. 'Cock' could refer to a rooster perhaps in a very strange context related to a'spooning story' which might be about people lying closely together like spoons. But it's all very ambiguous.
That's an odd situation. Maybe you were in a hurry and the clock was in your hand while you were near her backpack, and it accidentally slipped inside. It could have been a small alarm clock or a pocket watch.
I'm not entirely sure what you mean by 'cooking slipped in her casserole'. It could be a very unique or accidental situation. Maybe you were trying to transfer some cooked ingredients into the casserole dish and it accidentally slipped in an unexpected way.
Another moral could be related to the cycle of nature. The rooster is a part of nature and its interaction with the girl can symbolize how humans are also part of nature's web. We should respect all living beings and their natural behaviors. If the girl was initially scared but then learned to co - exist with the rooster's sometimes - erratic behavior, it shows that we can adapt and find harmony with nature.
If we consider 'it slipped into mom story', it could be that there was a certain object or concept that got incorporated into a story centered around mom by accident or without much thought. Let's say a story was being told about mom's cooking, and suddenly a story about a kitchen gadget that she used once'slipped into' the cooking story. It might have been added because it was related in some way, like it helped her cook better, or it could have been just a random association that the storyteller made while talking.
It could mean a story where a wife made a mistake or had a slip - up. Maybe she accidentally revealed a secret, or made an error in judgment in a particular situation.
If we assume 'cock lolipop' is some sort of fictional or unique item, perhaps the story could be about how she discovered it. Maybe it was in a magical land and she found this strange but wonderful 'cock lolipop' that had some special powers.