When a wife is having sex with her
husband and wants to get it over with as quickly as possible, she
will typically instruct him to put it in her ass.
This expression has come over into everyday usage as a way of expressing urgency or impatience, when you want to take
charge of a situation and bring it to a swift end. Especially useful when the action that needs to be taken is blatantly obvious to everyone involved.
Ugh, you've been hogging the drinking fountain for entirely too
long. Just put it in
my ass, already!
Robert, your work on the Henderson file has been spectacular. However, our deadline is looming, and you still need to interview four witnesses. If we're going to win this case, you need to step up and put it in my ass.
This has been great, but I've only got five minutes until my lunch
break is over. Put it in my ass!