Abstract: A flexible foamed or solid rubber mass is produced on a substrate by ejection. Two pressurized containers are used, one containing an aqueous latex dispersion together with a pressurized inert propellant and the other an aqueous coagulant solution together with a pressurized propellant and the solutions are ejected simultaneously from two vessels so as to converge on the target and impinge thereon at spots distanced from each other by not more than 50 cm.The invention also provides an apparatus for carrying out the method.The invention is applicable whenever it is desired to produce instantaneously a flexible foamed or solid rubber mass on a substrate. One of the important applications of the invention is self-defense and the combatting of riots.