Using a power wisk, whip one pint of high-quality fat-free milk until it has expanded to about two litres or so. (Not a dining experience for the sub, but the side-effects don't last as long.) Feed to sub, careful about breathing, minimizing swallowing of air, and watching as the stomach expands just above the navel. When sub is in pain, stop feeding and gently stroke the nipples, which may have heightened sensitivity. After a few minutes begin carefully burping sub. After several more minutes full-bladder play is an option. After-effects should be limited to an hour.