Fed button when visiting friends

Once you finish the Jingle Bell Wreck part 9 you can start sending feds to your neighbors towns. When you visit your neighbor you can either tap on the presents or click on the fed button (top right of screen). You can send up to three feds per town (or you can send one fed & collect two presents, send two feds collect one present or just tap three presents). I believe the feds are supposed to earn you more presents if your neighbors don't tap the feds. It is similar to grem alien eggs, I assume. It might be better to wait on using the feds for a little to make sure we are actually getting credit for them. I sent them in two towns and didn't notice that I got anything (presents) for them.