Usually just whenever I feel like it. Sometimes it's before dinner I usually rarely have dessert when eating out, just because I'm usually so stuffed with good food before it's time to think about dessert.
Not really a special occasion or every time type of thing. If I'm in the mood for dessert afterward, I'll have it. If not, then no. Sometimes I'm too full and even though there's something yummy like chocolate cake, I just can't stomach anything else.
I usually eat desserts on special occasions. Today was my nephew's birthday, so I actually did eat some yummy cake after dinner. Due to my health issues, I rarely have much of an appetite, so dessert is a rare treat for me.