Very easy if you have 2nd controller or a friend to help
From main menu:
-Minigames
-Tumble
-Select online game & public game
-Set gametype to Snowballs
-Create
-Press
on 2nd controller and sign in as guest or other account on your xbox
-Press
to start
-Once it loads quickly ready up (
) on both controllers so you are only people in first round
-Hit your 2nd controller 25 times with snowballs (
) (Be careful not to hit your 2nd controller off the map as it has to be done in 1 round)
-Achievement unlocked