The endpin on a Stagg EUB is one of its greatest design flaws. It moves around a lot, always rattles inside the bass and it is too short for people taller than about 6 feet. Besides that I find the rubber tip to be pretty slippery on a wooden floor (at least the tip on my new Stagg was).
Due to the design of the Stagg the endpin has to be very long. With it being only 10 mm in diameter it becomes pretty wobbly. Being so long it has a lot of leverage and the pin moves around in all directions while playing. The end of the pin rattles inside the bass due to this movement.
The major issue here is the endpin plug being made of plastic! The fit of this piece in the bass is not very good. It is cylindrical instead of conical as on a normal DB and it is held in place by two small screws hidden under the string holder. The fit of the pin in the plastic plug is not very good either… Rather sloppy…
The rattle inside the bass can be cured (to a certain extend) by wrapping some duct tape around the end of the pin that is inside the bass. I also tried a piece of heat shrink tube but that came loose eventually.
I replaced the rubber tip by turning an aluminum adapter to be able to fit a 12 mm rubber tip I had lying around from another bass. These rubbers come in different sizes and are used on walking sticks. I have used them on three of my basses and I find them to be non slipping, durable and cheap.
As the smallest available size is 12 mm I had to make the adapter. So I turned the adapter , heated it and then shrunk fitted it to the end pin. This solved the problem of a slipping pin once and for all, even when playing sitting with the bass at a larger angle.
I still have to find a more definitive solution to the rattle and excessive movement of the endpin. I will probably turn a new plug from hardwood or aluminium to replace the plastic one. But as this involves removing strings, bridge and stringholder and quite a bit of work, I keep on postponing this…