Use this card with "Limit Reverse" - Special Summon it on your opponent's turn (most efficient during their End Phase), then switch it to Defense Position on your turn, destroying it with "Limit Reverse" and activating its effect. The same can be done with "Gusto Gulldo".
This card's 1800 DEF is quite good for defense, but "Thunder King Rai-Oh" and "Flamvell Firedog" can still run it over via battle. Using "D2 Shield" can be somewhat good idea, since it will double "Squirro's" DEF so most commonly-used monster cannot breakthrough it, or at least force your opponent to destroy it via card effect, triggering its own effect as well.
This card can also provide additional defense in case your opponent attacks with "Ally of Justice Catastor" to cripple down most of your Gusto recruiters.
This card combos well with "Shrine of Mist Valley", as you can Summon both a high Level Gusto monster and a low Level one in one fell swoop. This can either provide you with an easy means to use the effect of "Reeze, Whirlwind of Gusto" or to Synchro Summon a high Level monster quickly.
If using the aforementioned "Limit Reverse" for Triggering this card's effect, this can enable Sphreez OTK option (assuming you have another Gusto recruiter and your opponent have strong enough monster).