Basically;
a) Don your wetsuit, and fill up your pockets with something villagers won't ask for - tools, seashells... I can't think of anything else, I use seashells personally.
b) Hop in the ocean, and set your game down (or swim around if you want, maybe catch some sea creatures) for 5 minutes. I usually go by the games clock and wait 6 just to be sure.
c) Get out of the water, and start walking in front of all of your villagers who are currently outside. One of them should ping.
d) Repeat until you get a request.
And since they won't be able to ask to buy/sell things, chances are higher that they will request a PWP. They may also ask you for catchprhrases or nicknames and all that, but hey.