I saw something on Pinterest about making cakes even more moist by spraying them with a boiled sugar water solution before putting on your buttercream. I don't really have a problem with getting a moist cake but I have never heard of this. Has anyone else?

Its called simple syrup.  But I've never heard anybody spraying it on.  Just brushing it on will do. Use a pastry brush.

AYou can flavor your syrup too, with liqueurs or extracts. It ups the flavor a bit. I put mine in a squeeze bottle because I keep forgetting to buy a spray bottle. Spraying would put a lighter more even amount of moisture. I don't use it all the time, but white cakes can usually benefit from a bit of syrup.

I also sometimes use a simple syrup in a squeeze bottle on certain cake recipes.  I have a carrot cake that I do that is very good, but it is AMAZING when I add simple syrup to it.

Vista, do you use yours plain or add flavor to it?  For the carrot cake.