An air hose is very convenient to get a safe distance between you and the rocket while pressurizing it.
It can be made very easily with some length ( minimum 10 meters ) of flexible reinforced plastic tubing, for sale in every DIY shop. You can also use a "real" air hose. Never use the simple clear plastic type of hose, used by aquarium hobbyists.
At one end, a compressor valve fitting is inserted in the tube and fixated with a hose clamp.
At the other end, an automotive / bicycle Schraeder valve is inserted and also tightened with a hose clamp.
A tyre valve can easily be retrieved from an old bicycle inner tyre - the new ones are almost all Schraeder valves (the larger type of valve ) or from the inner tyre of a wheelbarrow or motorcycle.