A drywall compound dispensing system for applying drywall compound to a wallboard has a delivery tube for delivering drywall compound entirely therethrough provided with a supply end connected to a source of pressurized drywall compound, and a dispenser end opposite to the supply end connected for pivotal movement with a drywall compound dispensing head. A tandem control lever arrangement is located at the supply end of the delivery tube and is engaged by one hand of the user for supplying manual or continuous flow of drywall compound through the delivery tube, and disabling pivotal movement of the dispensing head.