Its the raunchier version of the
fake moustache. A phenomenon sparked by Members of the republic of Movember who fail to grow a substantial mo. The
fake moustache used often resembles a
Merkin rather than a real mo.
Mokin can also refer to a moustache that is poorly maintained or is one of sparse or irregular growth and resembles pubic hair rather than facial hair.
Hey
mate, that mo looks like it belongs between your
legs... is it a
merkin? Ha, of course not, it's a Mokin!