Go to each browser tab and select the Smurfs & Co tab (second one as you can see below)
Do this for every tab, DO NOT CLICK SEND yet!
Once you have all tabs done and they all loaded the friends. Select in each tab the same friends (first 20 for instance) and send. Your friends will get a request for every resource, once they accept, you will see your message center getting filled with resources to accept.
You can also click for instance 5x gold dust and using the steps above also , so same friend will get 5 requests then for gold dust. Do know once you click send that those friends will not show again for 24h. This can also be done by sending as gift, we have the links here. Just do the exact same steps as explained here.