This is from a travel guide and obviously not advice for this country.
HOW TO PASS A BRIBE
1. If you are hassled by an official, be friendly, but aloof.
Do not show concern or act surly. Remain calm and good-natured. Try to determine if there is an actual problem or if the official is seeking some additional, unofficial compensation.
2. Never blatantly offer a bribe.
If you have misinterpreted the official's intentions, you may get yourself in additional trouble by overtly offering a bribe.
3. If you are accused of an infraction, ask to pay a fine on the spot.
Say that you would rather not deal with the mail or go to another location, citing your fear that the payment will get lost. Mention that you want to make sure the money gets to the proper person.
4. Try to speak to and deal with only one official.
Speak to the person who acts as though he/she is in charge. If you offer money to a junior officer while a superior is present, the superior may demand more.
5. Offer to make a "donation" to the official's organization.
Say that you would like to pay for gas, uniforms, car repairs, expenses, or other needs.
6. If you do not have cash, be prepared to offer goods instead.
Watches, cameras, and other electronics are often accepted as bribes. You might consider offering goods instead of cash even if you have the money, particularly if the "problem" concerns these goods. If, for example, a customs official tells you that you are transporting too many bottles of liquor, you might speed your trip and lighten your load by offering some of the items in dispute to the official.