CGSociety

An illegally staged and unregulated boxing match - early to mid-1900s.
(http://boxrec.com/media/index.php/Smoker)

A 'smoker' bout was for all intents and purposes--a professional prize-fight conducted under the auspices of a private, charitable club in those jurisdictions which prohibited prize-fighting, but that allowed,
for example:
'Sparring or fencing amongst members of private clubs for exercise only or for the enjoyment of their fraternal brothers.' Thus, many 'amateur' bouts were fought in the various American Legion posts, Eagles, Elks, Knights of Columbus, and other private clubs for their 'members.' Anyone wishing to witness a match was required to obtain a membership card and levied an assessment for the seat. The boxers were paid 'training expenses.' The authorities generally turned a blind eye to these bouts. When pressed, the promoters termed these bouts 'amateur.'

The term "smoker" may have originated from the clouds of tobacco smoke which swirled above the ring during these shows.

The Nymphs own magic and believe in luck. Thus, 'Knock On Wood(y)'
(prone on floor)
has special meaning for them, promoters, fighters, all. Even the
ring-side skeptics are impressed.