What is the rule on a quick tap, when can and cant it be done. It seems that every game i watch it is different?

If the player who catches the ball runs himself and does a quick tap once all his team member are also behind the 20 then it is fine. If he passes the ball to another player or a different ball is used then it's not allowed. Also not allowed if any team mates are in front of the 20 as they are offside

Yup, the man has to gather the ball himself. He can't have it handed to him by a ballboy / spectator. It has to be the same ball that went out (there was an instance on Sky recently - think it was the Hull derby - where a player got a ball off the ballboy and tried to take a quick tap but was called back) and the tap has to be taken on the mark on the 20m line.

Ridiculous rule

If the OP means a 20m tap then what's already been said is correct (and I agree with the rule, it stops the team taking the tap getting an unfair advantage).
If it's about a tap from a penalty then I've no idea because it seems to be different each time.

tap from a penalty is a controlled restart. Its taken whenever the referee wants it to be.

Yep, dumb rule.

I don't agree, it seems entirely logical. If a player can gather the ball and get to the 20m line before the opposition is set, he's won the right to a quick tap.

Having someone like a ballboy or spectator fling the ball to someone ready to tap essentially gives the team an additional player. It also clearly unfairly benefits a home side over the away side.

Now as for whether a player who has gathered the ball can pass it to someone else on their own team to take a quick tap, I'm indifferent as to whether they should be allowed or not. Currently they're not, and I don't really see any reason to change it.

Yeah and some referees seem to allow "quick taps" whereas some don't. A bit of consistency wouldn't go amiss.

Surely a quick tap after a penalty should always be allowed as it's really just another form of "playing advantage". If the opposition then tackles from an offside position, then that should be another penalty. Not even sure why the "tapping team" would all need to be onside prior to the tap as long as they were not involved in, or interfering with, the play.

It's not playing advantage, it's penalising the defence twice. When a penalty is given the defence is immediately offside, they should be given chance to retire the 10m required to put them onside again.
I wouldn't object to quick taps from penalties if the team taking the tap had to take the defence as it is when they take the tap. Ie if a defender is only 5m back instead of the required 10 when the tap is taken then he wouldn't be penalised for being offside.

But I don't like the "Union style" quick tap rule because defenders can't just magically and immediately retire 10m.

The attacking players need to be onside because it's consistent with every other controlled restart of play we have in RL, not that it'd matter much because there are very few incidents where attackers would be ahead of the point of a penalty anyway.

The whole rule needs looking at again. Especially as the NRL play a different rule to super league & internationals are different again. For me it is a good skill to have but as I have advocated on other threads it should be a proper tap, place the ball on the floor play it forward with the foot then pick it up, not wave it in the general direction of your boot while running at full speed. That is how the tap was in both codes in the 1960's it rewarded attack if done properly but also it was a risk as there was always the risk of a knock on especially on a wet & muddy pitch. A player had to take that into account when choosing the quick option.