Yes. My experience: do it a bit in advance at least an hour and eat pretty light. The more you exercise and eat clean, the better it will be. Also drink lots of water to avoid getting dehydrated. Enemas will definitely help avoid messiness. Search the board, as there have been discussions about it in the past.

i have learned to definitely do it, about an hour before your visit will suffice.  there are plenty of places to get simple directions regarding how to.