launch a steamer Share definition Flag The grueling act of straining to push out an impacted bowel movement. To take a very huge, painful shit. If you feel you're gonna launch a steamer, it would be wise to drink some prune juice. launch a steamer by Matt Eros November 9, 2007 0 0 Get merch Get the launch a steamer mug. Buy Now — $32.95 See more merch