It's important to read through all the information given on the B&P's. (those links I gave)
You definitely ARE going to have to force yourself to drink water while doing the b&p's or you'll just get stopped up. I reeeeally disliked drinking water before I started all this cleansing. I'd go days without drinking water! Or have 1/4 cup a day and that's it! I've found that I like to drink my water out of a glass wine bottle. (I've turned my friends and family on to this too - people that haven't been able to drink lots of water somehow find this method good - it's easy to see how much you've drunk and you don't have to chug a glass all at once...)
Also...what do you mean 'when the b&p's will kick in?'....you know that they don't make you have diarrea, right? They are more constipating than anything. There is no running to the bathroom with b&p's. Hopefully in the morning you'll feel the urge to have a regular bowel movement...but it does take at least 24 hours for the b&p to work through your system...to do it's scrubbing thing...so don't expect mucoid plaque right away.