What would "overspill solutuion" mean?
It would depend on the context, I you mean. Please use it in a sentence at least. :)
Overspill is where there are too many or too much of something for an area- you can have overspill where there are too many people, cars, etc, in a city, for instance, so the solution would depend on the type of overspill.
If you find yourself in a situation where you realize that are talking way too much, here is a solution to the situation. Give the person you have been talking to a complement, telling them they are 'easy to talk to' and that they are such good listener. This takes the focus off of your 'overspill' or talking too much and shifts the focus to your weary listener, trying to make them feel good about their patient listening, at least.