Negotiating the floor can take on epic proportions at times with your interlocutor when you both want to get something out. In the following two examples, David Davis and John Humphrys almost end up rapping together as they fight for the floor with each other!
In general, only one person can hold the floor in a conversation. When a debate is taking place, there are often periods where negotiation of the floor occurs. The current speaker will use rhetorical devices to try and maintain the floor while other participants in the debate will interrupt and overlap in an attempt to gain the floor.