bullet sponge
n.— «Marines -> Bullet Sponges.» —“Re: Interservice derogatory nicknames” by Steve Sample Usenet: alt.folklore.military May 25, 1994. (source: Double-Tongued Dictionary)
Further reading
The Texas Folklore Society’s book The Best of Texas Folk and Folklore, 1916-1954 (Bookshop|Amazon) offers some wonderful browsing, including this saying to describe an environment that’s too loud: You can’t hear your ears in this place...
For rock climbers, skiers, and other outdoor enthusiasts, the word send has taken on a whole new meaning. You might cheer on a fellow snowboarder with Send it, bro! — and being sendy is a really great thing. Plus: a nostalgic trip to Willa...