I cheat on Sunday. I usually go out and get something I don't normally have like a prime rib steak or some such thing and a good size serving of Sweet Potato. I always follow up with something sweet just cause I know that for the rest of the day and the following six I will be out of luck.
This usually reminds me why I eat like I normally do, cause I feel like crap and psychosis starts to kick in immediately.
On my cheat day I cheat an insane amount! I know it would be better not too, but aparently so far I can get away with it. I drink all the beer I can and eat like shit all day.
Ditto Pintoca how it should be a cheatmeal as opposed to a cheatday.
Anyway, for me it's generally more carbs + flavors (eg: sugar & fried food) for example: a plate of Tempura prawns (Tempura = fried/battered bread crumbs) and a side dish of fried garlic rice would be a cheat meal for me and some Japanese milk tea.
All you can eat type of food for me would constitue multiple cheat meals at once, which I consider overconsumption of junk food in one go. I'd rather seperate that in say two small meals - at least better for my digestion.
BTW, It is always a better idea to have your cheat meal on your high-cals/High-carbs days. You are going high on those days for a reason (leptin, T3) so it dovetails nicely with a chat meal.