I feel the best time to take coconut oil for constipation is morning. Why? If you ingest coconut oil in the morning and if it triggers diarrhea on you, you still have sufficient time to let the unpleasant effect wear off.
Some people ingested coconut oil in the evening in a bid to ease their constipation. Guess what happened? They got the runs. The effect didn't wear off by the time they hit the pillow. They ended up staying up the whole night just to finish up the "business".
However, if morning isn't feasible for you as you need to go to work or for some other reasons, do it at night before you sleep. Won't you get diarrhea from coconut oil that way?
The situation I just mentioned usually happens to those who take 2 tablespoons or more. And it gets worse when they ingest coconut oil on an empty stomach.
In view of that, just take ONE TEASPOON before bed will do. I guess your stomach should still have a little food left from dinner to slow the digestion of coconut oil. Hopefully, this tactic won't affect your sleep and will give you a good constipation relief the following morning.