Funch is a Southern variation on the more common usage of funch - a combination of "fuck" and "lunch." In the SouthwestUnited States, funch is used to refer to something you will fuck then eat.
Funching is the greatest thing ever and I´m sure you´ve done it: you´re in bed and you´re uncorfortable because your pillow is roasting due to your enormous hot noggin, so you flip it over to the cold side and enjoy!