Can't get many-to-many relation but attach/detach works correctly in Laravel 5.2

Full error is:

1066 Not unique table/alias: 
SQL: select `salons_services_salons_services_sex`.*,
    `salons_services_salons_services_sex`.`salons_services_id` as `pivot_salons_services_id`,
    `salons_services_salons_services_sex`.`salons_services_sex_id` as `pivot_salons_services_sex_id`
from `salons_services_salons_services_sex`
    inner join `salons_services_salons_services_sex` on `salons_services_salons_services_sex`.`id` = `salons_services_salons_services_sex`.`salons_services_sex_id`
where `salons_services_salons_services_sex`.`salons_services_id` = 92

Model:

class SalonService extends Model
{

    public function sex() {
        return $this->belongsToMany('App\Models\SalonServiceSex',
            'salons_services_salons_services_sex',
            'salons_services_id',
            'salons_services_sex_id')
        ;
    }
}

Trying to get related records with $service->sex is leading to error, but attach() or detach() works correctly so I can link models with this methods.

via Chebli Mohamed