When working on projects I often need to plug my DMM leads into my bench power supply to test PSU voltage, current drain, probe voltage onto the circuit, etc. My PSUs have banana female plugs, I only use the spade side of the plugs, not the front holes. I tend to poke the test leads into them “hoping” I will get an acceptable contact and that they will stay, it never really works well.
In one of me connector box, I have many old automotive type connectors I don’t use, the one of interest is a bullet plug (circled in the picture below).
The bullet plugs fit well in banana female plugs. If you remove the plastic shroud and modify the ring to fit your test lead, you can then insert the plug into the banana female plug and use it to connect your test lead. The test lead will penetrate all the way to the end, and this can easily be done with one hand … whilst your other one is busy holding something else.