how to insert in two tables data from one model in laravel code example

Example: insrt data in two tablesuse laravelonce

class Something extends Eloquent {

    protected $table = 'something';

    public function users()
    {
        return $this->hasMany('User', 'id_something');
    }
}

class User extends Eloquent implements UserInterface, RemindableInterface {

    use UserTrait, RemindableTrait;

    protected $table = 'something_users';

    protected $hidden = array('password', 'remember_token');

    public function something()
    {
        return $this->belongsTo('Something', 'id_something');
    }
}