Whenever you fetch tenants using an eloquent query, you'll get returned an instance of Spatie\Multitenancy\TenantCollection. This class extends from Illuminate\Database\Eloquent\Collection so you can use any of regular collection methods that you know and love.
In addition to the regular methods, TenantCollection provides four extra methods: eachCurrent, mapCurrent, filterCurrent and rejectCurrent. All these methods work like the regular each, map, filter and reject methods, but in addition they will automatically make the tenant the current one.
Tenant::all()->eachCurrent(function(Tenant $tenant) {
Tenant::current()->is($tenant);
});