look up any word, like b4nny:

1 definition by brandonhasnoclue

 
1.
FBN
The event when one's caloric intake kicks in after a large meal, and said eater becomes very tired. Keeping one's eyes open proves challenging, and an approaching full belly napsie becomes evident.
After all that Indian food and this long cab ride, I feel a FBN coming on!
by brandonhasnoclue August 17, 2010