How and when would you use Victini's "Victory Star" Ability to reflip coins when using Mamoswine's "Ramming Strike" attack?

Anytime during the course of Ramming Strike, you can use Victory Star once to start the attack over from the beginning. Any damage counters placed on Mamoswine during the course of the attack would be erased, even if it is enough for Mamoswine to be KO'd, and Mamoswine basically gets one more chance at using the Ramming Strike attack.

Relevant cards

BWP_BW32