Sexual act, originating from east african gangbang culture. Often practiced by maturing gay couples, hailed as the perfect "safe" sex act. One male sticks his penis inbetween the other males gooch and inner thy. The recieving male proceeds to vibrate and jostle their abdomen up and down in order to stimulte the other males penis.
Ryan: Hey Will, honey. Don't go just yet, lets FunGum.
Will: Oh babes, you know me so well. Come here now.