To Boff is to close a deal in a sales environment with little or no hope that the deal will stick or an invoice raised pertaining to the order will ever be honoured.
It is an effective sales tactic only if you know you will be in a job no longer than 3 months.
Effective ways to "Boff" would be to uncover personal details by playing a game.
i.e "Can I guess your bank details?"
Or to do it by sleight of hand. i.e. "If you give me your address I can send you out some information" in the full knowledge that you will gain bonus from this poor schmuck whose getting some junk mail they may never make use of.
Excessive "Boffing" can lead to unemployment or excessive office bitching and should be avoided at all costs.