What are you using it for, competitive battling or in-game. Competitive Battling use milotic(it's defenses help).
In-Game: Though i prefer to use an "offensive" Walrein, example: one that has moves that attack don't defend(MAYBE KEEP REST THOUGH,but only if you have a chesto berry.) Ohh yah and i find that
SURF
ICE BEAM
DEFENSE CURL
ROLLOUT
Works pretty well but i would usually use; Surf, Ice Beam, Body Slam and rest. But i will also usually have a chesto berry attached(with the other move set you can attach something like leftovers.)