Sometimes when your online in CoC, you need to increase your donations but there isn't anybody else online due to timezones or something. So the only way to donate to someone is to donate to an open request.
My idea is that you can send a donation thing in clan chat, that you fill with your own troops. When someone comes online, they can view your donation thing in the chat and fill their CC with the troops you sent. So the player gets your troops and your donations increase. I think this will really help in clans with players in different time zones.
Maybe the amount of troops you can send in a donation thing depends on how big your CC is.
So basically this allows you to donate to people when your not online