Suffumigation is the act of burning something to create smoke or fumes as part of a spiritual or magical practice or ritual. It specifically means “fumigation from below”.
Suffumigation may be used to burn resins in offering to a spirit or deity or to attract certain spirits. Or it may be used to purify an object by placing the object over the burning substance so that it is “bathed” in the rising smoke or fumes.
This is pretty much synonymous to smudging, but smudging implies the use of dried herbs, and suffumigation implies the use of incense or resins. This isn’t a defined rule, just sort of a context implication.