Humorously used to refer to that part of the stomach reserved for dessert. Especially well developed in teenagers, this allows a person eating a large, group meal such as Christmas dinner to be full on meat or vegetables, but perfectly capable of eating multiple servings of cake or pie. Example: (Everyone is sitting and commenting about how full they are. Dessert is announced.) Someone (often a grandchild): Some pie sounds good to me. More senior family member: You have quite a dessert pocket there.
DESSERT POCKET
Meaning of DESSERT POCKET in English
Slang English vocab. Английский сленговый словарь. 2012