Sit in the milk....no way! As long as they can "smell" I think you should be fine -- the warm milk should help with that. Think of it this way, Aromatherapy for worms!!! :)
Actually, it might be a good idea to rub a little milk and/or honey on the rectum. One other thing, while sittin' on the pot stack a few telephone books on the floor and put your feet on the them and lean slightly forward. This should help open up the area.