the UnCool dictionary: "Bur"

"Bur" (p. b-err)

to proclaim obsuredity of an action, act, situation, or statement. (can also be used as positive confirmation.)

Sentence: "Can you run me over to walgreens 4 ...(squint's face b4 response)"Bur?" (vague look.)
-or-
"...and then she asked me if my roomate was here, cuz she wanted to come over...(and spend the night?)..."Bur" :-)