it depends on the person, but lots of ladies like to detangle when their hair is wet with conditioner still in it and then rinse the conditioner out after they detangle.
i prefer to detangle after i deep conditition and rinse the product out, but while my hair is still soaking wet.
I agree with havilland. In the shower with lots of conditioner. But what has been saving me is S Curl Activator (blue and white bottle). I just spray it near my tangled roots and finger comb. I do this with my hair either damp or dry. Even my hairdresser noticed that it was less tangled this time around when she put my relaxer in (I was 13 weeks post).
My last relaxer (texlaxed) was in February. I lightly detangle with my fingers before I step in the shower, then do the same under running water. I use a wide tooth comb after soaking my hair in conditioner. I find that brushing my hair works best when my hair is damp only. I lose a lot less hair that way, and it stays detangled too.
The pressure of water activates the slip in conditioners. After its washed, apply conditioner then put hair under running water as you detangle, its amazing...Comb slides right thru.
I detangle under running water while washing out conditioner also. I use my Denman brush (I removed every other bristle) and just make sure to remove the majority of my shed hairs while under running water.
During the damp stage when I apply my leave in most of the detangling has already been done. At this stage I work in small sections only.