You need the Spoot the Magic Llama cheat for this.

Got to the mailbox and hit LT, then press A and a list will come up.

Go to "make friends for me" and keep doing it about 10-15 times until you think you have everyone in town.

Then go to you phone and choose "call sim". Choose a hot young adult/adult from your call list and ask them to come over or go out to eat or something with you.J

ust start flirting with them and it will work fast.