There are two places you can Defer a Topic.
The first is in the dot menu to the right of the topic.
The second is located on the bottom left of the timer when the topic is being discussed.
This will move the topic to the bottom of the agenda, and can be brought back into the agenda when it's ready to be discussed.
Read more about it on our blog: http://instantagenda.com/deferring-topics-later-discussion/