You should not interpret this a being suggestive.
However, as Dan pointed out, the most important resource of ANY real estate professional is the willingness of their past clients to recommend their agent to family, friends and neighbors.
To prepared to answer, "Who do you know that would benefit from the same level of service you have received that is considering moving or buying a home?"
Provide that list before closing and it is more than likely an exceptional surprise is in YOUR future.
The best bonus any agent can ask for is your recommendation to friends and family. There is no "tipping" rule like at the local restaurant or bar. Occasionally a seller may offer a bonus, larger commission or other inducement to an agent, but this is not your responsibility.