Good question, The Percy
Tackled player has usually been heading for the line before being tackled short, so scenario is often that he hits the deck facing North/South in relation to the orientation of the pitch (i.e. parallel to the touchline). Let's look at the simple decisions.
- If, having hit the deck, he immediately reaches forward and grounds the ball on or beyond the goal line, award the try.
- If, having hit the deck, he recognises his reach will be insufficient, and so crawls forward and then reaches to ground the ball on or beyond the goal line, award a PK against his for failing to release the ball in the tackle.
Between these two simple decisions, there are myriad more nuanced ones. The thinking is the same though. It's either a try or a PK for failing to release in the tackle. It's impossible to legislate for every possibility, but I think it is possible to identify some principles - though some will doubtless be considered controversial.
- you can legitimately slide until you stop naturally, and then reach out to score
- if you use any part of your body to get your torso closer so your arms are within reach of the grounding, penalty against
- if you are tackled so you lie parallel to the goal line facing your own goal line, the permitted reach out can include the necessary half-roll
- if the tackler lies between you and the goal line, any attempt to score is most likely to result in a PK against
- If you reach out to score and fall short, you have exercised your option and cannot then drag it back to place it behind you - PK against for failing to release
Others will doubtless add a few, and debate a few.