Service was originally a noun only, but it has a few longstanding verb definitions that most dictionaries accepted long ago. Some of its verb senses have sexual connotations that can arise unintentionally when the word is used in nonsexual contexts.
The nonsexual definitions of service as a verb are (1) to make fit for use, repair, or maintain; and (2) to make interest payments on a debt. But another long-accepted definition of service is to copulate with. It usually applies to the role of males in animal breeding. A less accepted but widespread definition is, simply, to have sex with or to perform a sexual act with.
Given these definitions, it might sometimes be best to avoid using service with a person or group of people as its direct object. If serve doesn’t seem a fit replacement for service, try aid, assist, or help.
Service in the sexual sense is not rare, so we can’t just ignore it. Here are a few examples:
But Lee dismisses as “nonsense” reports that female “pleasure squads” were trained to service him. [USA Today]
For 14 months she serviced the sexual needs of “between dozens and hundreds” of men. [Herald Scotland]
As we already know, Judith disapproves of premarital intercourse, but allows Darren to service her vigorously. [Salon]
Under Islamic law, a husband is fully entitled to beat his wife if she refuses to service him until she finally consents. [Right Side News]
Either we’re dirty-minded, or these instances of service are unintentionally icky:
I had an amazing team of professionals and we serviced our customers like distinguished guests. [posted on San Francisco Chronicle]
We’re about servicing the fan all day long. [quoted in Los Angeles Times]
And these instances of service are okay because the direct object of service is inanimate: