Its what you say when you are not sure how things might turn out, when you are playing risky. It's akin to "kiss your butt goodbye" but it's closer to "kiss your toes goodbye".
Alex was driving really fast down a slippery leaf hill when Tora exclaimed, "kiss your dogs!" And then Lonny giggled effluvently.
Worse than every insult combined, including "your granny tranny". This would be a final resort in an argument as it is unlimitedly powerful. If this insult is used against you, there's no chance of survival.
Person 1: Your mom gay Person 2: Your granny tranny Person 1: Your doggy soggy
Person 2: *Asphyxiated by an unknown force, possibly the unknown power of the insult*