For someone (actor muɴ-) to dirty himself, itself (loc ref) by coming in contact with something that soils the body (theme), as for a drunk person to fall in mud, children to play in a dirty place, a carabao to wallow.
For someone (agent; s agent mangi-) to soil someone or something (theme i-) either intentionally or unintentionally; e.g., by dropping something in mud.