Okay, so an offset agreement is when your mommy or daddy give you a candy and you have to do something in return for them. It's kind of like a trade, but you're not trading the exact same thing.
Now, let's imagine that mommy or daddy wants to buy a big toy for you, but they need to buy it from a store far, far away. The store is too expensive, so mommy or daddy asks another country to help them pay for it.
This other country agrees to help but tells mommy or daddy that they have to do something in return. They don't want money, instead, they want mommy or daddy to help them with something else, like buy something from their country or use their services.
This deal, where mommy or daddy have to do something in return, is called an offset agreement. It's like a trade, but instead of getting something for the exact same thing you give away, you get something in return for doing something else.
So, in the end, mommy or daddy gets the big toy they wanted for you, and the other country gets something in return. It's a win-win situation!