How do I make a system where if I click it does something and when you click again it stops that thing

As seen in this picture I am attempting to make it so when the stick hits the puck, the velocity of the
puck changes then goes back to default (15) then when you click again it does not change the velocity.

How can I make when clicked again it doesn’t do he same function; (this):

Could it ever be hit again or is it a once only event for the puck?
If once only, you could add a Boolean tag to the puck. When hit, check if the tag exists, if yes then increase velocity then remove tag. Any subsequent hits will see the tag has been removed, so wont increase in velocity.