If the ends of the couplers are threaded onto the hose take two wrenches and start to unthread the fittings. It takes very little movement of the threads to relieve the pressure. Whenever you take a implement off a tractor lower it to the ground, turn off the engine, then move the lever in the tractor in as many directions as possible 5-6 times to relieve the pressure. Then detach the implement. At that point there should be no pressure in the lines and it should be easier to attach next time.
PS- I am not too keen on hitting the end of the coupler metal on metal. See if you can find a wooden dowel or something similar. Hammer on the wood if possible.