>>12120199That seems oddly particular and it is hard for me to imagine that people would get off to that. How do you know this?
Also, it does not ruin the relationship so long as the girl does not find out, and since toothpaste has such a strong taste I think it would be hard to taste, let alone recognize, cum in toothpaste, even if the two substances were mixed half and half. Eventually your daughter could become accustomed to the taste, and if you ever stopped making her use your cum then she would notice. But I am thinking it would be hard to start putting your cum in the toothpaste in the first place.
Once you get toothpaste out of the tube, it becomes extremely difficult to get it back in.