Cubile--
I guess it has been about two months since I used.
Sexual feelings are the trigger. The cravings are usually about wanting to hold someone. Being intimate emotionally and physically. Wanting to be wanted. Or that is how I experience them.
They start and then I do things like make dinner or watch TV, and they persist. This goes on for a few hours. If I am lucky, I fall asleep. If not I am kept awake.