To encase, or otherwise stuff ones
penis and scrotum, a.k.a. junk, into a very
tight pair of leather pants. Smuffling is expanded to mean any rough tucking or handling, by oneself or others, of said junk, ranging from mild smuffling to extreme, drag
queen smuffling (may or may not involve surgical staples).
Smuffling is also extremely useful when attempting to defecate upon your own chest.