PNV - Chart, page-16124

T+2 refers to the settlement of your purchase or sell order.

As an example, lets say one purchases 100,000 shares for $1 on Monday, the payment does not go through until Wednesday morning.
With this in mind, and if the sp rose to $1.05 on Tuesday then you could sell the 100,000 shares at $1.05 and make a difference of $5000 (less your brokerage) within a day.

Now some risk adverse traders may extend their sell to the Tuesday auction (4pm-4:10pm) hoping to get another 0.5c, 1c, or more to maximise their return but also take the chance of losing and not even selling if they don't price it correctly. The auction is where the dance occurs on the indicative price, generally caused by t+2 traders making sure they get their sell or buy.

The mechanics are easy to understand, the psychology is another matter.