Hi Speedy, you can back every 2/1 shot with me then.
You put on $16.50 (to win $33) and I will gladly pay you $33 every time they win.

The bet to lose $33 @ 2/1 or $3 is........... $33 to $16.50.
The figure on the ticket (the payout) is $49.50.

If it wins, the bookie loses $33 and pays out $49.50.
If it loses, the bookie wins the $16.50 that the punter has bet.
It could not be more simple.

I've also had a bit of experience laying....around 29 years.
I do this for a living.