1. Male who has an abnormally large lower torso area. Enjoys to eat things quickly, preferably so fast he cannot taste them. Enjoys bacon, orange juice, and a good hot bath.
2. Tells ridiculous stories that could never possibly happen to any normal person in real life. No one doubts these stories because a gillerbutt is such a sweet nice guy, you would never think to doubt all of their harrowing tales.
3. Enjoys rousing local fire departments through a series of false fire calls.
Dude, that guy is so fly. What a gillerbutt!
Wow, that story about how you gave your cat CPR is a gillerbutt story!
No worries bro, Rich just pulled a gillerbutt move. No fire here.