Physical condition characterized by the presence of slippery shit residue in taint and anus region a the result of either: 1) failure to completely remove all shit during post-dump ass wiping or, 2) failure to completely expell all shit from body during dump, leading to the 'slow-leak' factor involving the slow excretion of shit matter through butt cheeks while walking or standing. While this phenomenon is often confused with 'swamp ass', a quick examination of one's underwear reveals a more prominent ratio of shit vs. sweat during the presence of dumpster butt.
During my lunchbreak at work today I carefully and quietly crammed a wad of toilet paper in my ass to quelch the dumpster butt i'd developed from my morning quick-shit.
Noun dəm(p)-stər bət
a) a rectum used as a large receptacle for all manner of cock, cum or instrument with no regard for health or hygeine
b) a whorish gay male
Gurl...you should have have scene it! He was al kinds of cracked out. He took two cocks at once and about 20 loads. What a dumpster butt! I still love him though.