Visitors should make an effort to learn one greeting in the local dialect. Paying for hospitality with money will put you in a very embarassing position and you may even be ripped off too as tourists have encouraged the prectice of begging among indigenous people. You may return hospitality with gifts of medecine, or food for the family or cloth to the elders. Smoking is prohibited in most places. The senegaleese are great smokers but it is more about politeness then prohibition.
Smoking is a private thing, specially for women.
Senegaleese only shake with the left hand when one is leaving for a long journey, it is a way of saying they want you to come back again.