Conjugation of the spanish form of Ustedes: "You all" plural. By simply adding the "B" to the formal form of spanish speech you are able to transform "Ustedes" into "BUstedes"
Describes the state you are in right after waking up from a longnap and you feel out of it and groggy. Nothing really makes sense and you can't think that well.
Deven felt bustered when he awoke from his late afternoon nap after a long day of mewing and edging, so he said "my gosh do I feel bustered!"