The hand job is arguably considered one of the simplest methods for delivering instant gratification, requiring little or no resources. But it has possibilities other than just the gift of pleasure, beyond even a role in a trade or barter system. For the apt user it can become a form of self defense.
It is well known that feigning death or otherwise assuming catatonic passivity, fails to deter many sexual predators, less well understood is that, due to an early human disposition for carrion feeding, an active response will always disengage pursuit much more effectively. The firm "No!", the blunt "Quit it", or even the calm-shattering, "Fuck off! Can't you tell I'm busy!" will often be successful, but perhaps the more amicable way to defer a persistently horny lover, is explore the phrase, " I'm sorry sweetie but all I can spare right now, is half a cup of lanolin and hand job".
Disarming by manual discharge.
While the blow job in North America has often been considered one of the better ways of sublimating a partner's drive towards sex, it does assume a certain amount of, in your face intimacy, perhaps a bit up close and personal. It is in itself, by most definitions "sex"**
A hand job, on the other hand, can effectively detour from the sexual objective without having to roll up both sleeves, or wade into an emotional quagmire of sex where you'll have to go elsewhere.
Performed at a functionary level, a hand job can be a medicinal therapeutic act. With practiced dexterity - sexual tension can be converted into lethargic indifference in a matter minutes, allowing attention to be returned to whatever was deemed more important.*
*noding, a book, unconsciousness
** or in some U.S. states sodomy | 
