What is Outgrabe?
1.
1. something between bellowing and whistling with a kind of sneeze in the middle
1. "...and the mome raths outgrabe." (Lewis Carroll, "Through the Looking-glass and What Alice Found There")
2. The kid behind me started outgrabing.
2.
most likly past tense of a verb, outgribe (strictly verbally speaking, the only available example is awkward (as opposed to say 'the mome raths were outgribing'), but the poet selected this marked form for rhythmic purposes)
correcting ex. 2 above:
The kid behind me started outgribing. When he had outgriben to his snout's content...