delicate version:

when penetrating someone's anus during intercourse, it is considered polite to reach around and manually manipulate the other person's genitalia.

indelicate version: (printed backwards so as to avoid undesired offense)

.boj dnah a meht evig dluohs uoy ,ssa eht pu enoemos kcuf uoy nehw

morgon77 tells me this is also the term to use when someone gives you a hand job during front-to-back vaginal intercourse (e.g., doggy style).

Also:
A recovery tactic employed by software companies when faced with the discovery that their product sucks; the opposite of "workaround." Involves giving you something nice to distract you from the fact that you're being anally violated. The most common reacharound is "it's not a bug, it's a feature."