Clarification on node please

The_One

Can anyone clarify the bubble shield node.
Is it if I hit his block or if he hits mine?

I've asked alliance mates and other friends on line and no-one seems to be able to agree.
A clearer description or clarification from a mod would be great

Rollingxbigshot

If he hits your block

Kerneas

This node is "ability" of that champion you fight, meaning that he hits you and your block decays

Mrspider568

Each block reduces your block proficiency