How to increase money between rounds in BTD5 for iPhone?

I've been playing the co-op online and in between rounds the play button has the circular loading thing and I click on the request or give button to see how much money partner has and I watch as their money increases while mine remains the same. I was wondering how people are doing this? They don't have any Banana farms so its not from those. It happens on all rounds and I can't figure it out.

I think you can copy him or something