M. is used for individuals who has regular and/or intentional intercourse with dirt or mud. It is a strong word which can be offensive in certain contexts.
- That guy seems to like mud unusually much.
- Yeah, that's because he's a mudfucker
An individual that has sexual intercourse with a mong
One exeption is group sex with mongs, this is genrally sick.
A Mongfucker is normally a mong as well.