How do you wago?

[Alan Anderson]

It does take three hand-using operations, but only two of them are necessary at a time. Hold the connector and push the tool/screwdriver in: the clamp opens up. Let go of the tool and you can use the now-free hand to insert the wire. Hold the wire in place with the same hand that's holding the connector and pull the tool/screwdriver out: the clamp closes and the connection is made.

If you're "prying" the clamp open, you're not pushing the tool in far enough (it might be too wide to fit).