As it sounds, have a lovely smooth white knob which is lacking in its ability to stay attached after a good tug.
I'll stop now, basically I'm after one of these:
In~ half inch diameter but I cannot find anywhere that sells them despite much hunting. Does the hive mind know of any suppliers?
I'll stop now, basically I'm after one of these:

In~ half inch diameter but I cannot find anywhere that sells them despite much hunting. Does the hive mind know of any suppliers?