To complete this achivment you first have to be level 14 becuase that's when you unlock the factory requests.
Once you are level 14 you will get a message from someone asking for certain pinatas. for me i had to send away 4 whirlms. Once you send them away, you will get them back along with a gift, i got two happy sweets as my gift. (gift and pinata may vary)
Repeat this proccess 5 times and the achivment is yours :)