As with all ideas in this folder this is a rough draft and must be
adjusted for the actual participants and desires.

The bottoms/sub/masochists/slave/etc will be called the contestents.

The basic room setup consists of 2 stations 5 to 10 ft apart.  The 'TOP'
station has a chair for the top and a spanking bench/chair/etc. for
the contentestant.  Maybe also a small table for the TOP's drink/snacks.
The second is the BOTTOM station.  This has a table holding a variety of
paddles/canes/crops/rods/etc. as well as a spray bottle of alcohol/lighter
fluid.  There is also a fire resistant chair (explained later).

Clothing:  The TOP dresses however they want ;)  The contentestants
wear a tight skirt/dress about knee length +- a bit and not as tight
as a hobble skirt would be.  An all cotton bra on top (see notes).
Stockings (not panty hose), cotton panties, garter belt and girdle or
panty girdle and a slip (full or half).  Clothing is the same for all
contestents and must be tested to make sure the material is non-flammable.
A leather belt may be used to help define the waist.

The play:  

The contestents line up single file at the contestent's area.  The first
contestent selects their desired implement and the contestent behind
them sprays their butt with the flammable fluid and then lites the first
contestents seat.  

The contestent then walks to the TOP and politely asks "Please give me
X swats" and hand the implement to the TOP.  The number of swats may be
preset for everyone, such as always 10 swats, or each contestent may
asks for the number they think will reliably extinguish their butt.
They bend over the chair/spanking bench/etc. to receive their swats.
They then walk back to the end of the contestent line.

Things that can happen:

1)  The contestent may find their seat too hot to get to the TOP and take
the requested swats.  This may require shortening the walking distance
or adding more panties/slips to slow down how fast their seat gets
overheated, if this happens too often.  The amount of protecton should
allow all contestents to make it at least 2 or three times through
the line.  Once the adjustments have been made then if the contestent
fails to get there they are a looser, but continue through the process
until a single contestent completes a cycle successfully.  An option
would be to add some additional punishment at this point.

2)  The contestent fully succeeds and gets back in line for the next
cycle.

3)  The contestent receives their swats, but their butt is still on fire.
They can put out the fire as soon as they leave the TOP's station without
penalty.  If they make it back to the contestent's station there is a
chair there with cold packs they can sit in to put out the fire and cool
their butt.  They don't get any extra points, but maybe some bragging
rights for having a tough butt ;)

Now that there is a winner the winner gets a reward.  Of course if you
want to have a little more fun the winner has to do another pass through
as a 'victory lap' ;)

Suggestions for rewards include:

a)  The winner gets to select the next contest.

b)  The winner gets to select the punishment for the loosers.

c)  The winner gets some prize, perhaps based on who the winner is.

NOTES:

There should be at least one or two extra people as spotters with fire
fighting equipment just in case.

As each contestent looses an additional torture could be added at that time, such as add swats on breasts, irritants on clit/labia, etc.

An alternative might be to set breasts on fire instead of butts or to
even alternate so each time through the line the contestent first gets
a hot seat and next time hot breasts.

I'm assuming a pump type sprayer for applying the starter fluid ;)
Depending on the sprayer the number of sprays should be between 2 and 6.

It takes time for heat to penetrate the clothing so the heat felt the
first time through the line may seem low but as each pass is made the
heat will get worse depending on how long the cooling period is.