The sixth touch is the high-risk attempt. Whatever happens on touch six, possession changes immediately after. The team that has thought about touch six in advance is the team that gets the most out of it.
There are three main options. The first is to score — if the structure of the set has produced a real opportunity, touch six is when to take it. The second is to move the ball as far up the field as possible so that even when the turnover happens, the opposition has to start their attack from deep in their own half. The third is tactical: take the touch in a position that makes the other team's first defensive set hard — for example, near a sideline so they're constrained on one side from the start.
The worst outcome is a turnover deep in your own territory. A team that forces a try attempt on touch six from a bad position often gives up exactly that — they turn the ball over in their own half and concede a try the other way within one or two touches.
Field position usually beats heroics. If the strike is not on, working the ball forward by 10 or 15 meters is a clear win — possession will change, but the geometry of the next set heavily favors whichever team is further upfield. The sixth touch should be used intentionally. A controlled turnover in a strong defensive position is often better than a rushed, low-percentage attempt.
The most common failure modes are forcing a low-percentage try attempt from a bad position, playing too cautious so no field position is gained, no one knowing whose decision it is on touch six, and worst of all — being surprised by touch six because nobody was counting.