You don't have to have a BM at night, see link from Spirit (webmaster) //www.curezone.org/forums/m.asp?f=447&i=8513
There are different protocols about flushing and they are all a little bit different.
Some say right side, Andreas says on your back with your head raised. The main thing is that you rest for 20 minutes, things move in the 1st 20 minutes. There is even a flush where grandma walked the whole night (under cleanses).
They all seem to work.
BTW next time when you do the Oxypowder you can just do the ES at 8 pm, or half it at 6 and 8 pm. I don't prepare my ES beforehand depending on my bowel situation I do between 1-3 tsp per glass. 1tbs=3tsp. I warm some water and disolve it first. The liver does not like cold so try to drink everything at room temperature.