This is a translation of a post that Sebastian Kawa sent to whatsapp a few days ago. Very nicely and clearly said and straight to the point!.

Dear gliding fellowsMany aviation and gliding traditions follow similar traffic rules and good aviation practices. Unfortunately, these rules are not part of international air traffic regulations and have never been published in official publications. Even in countries where such rules existed as national or club rules when international rules were introduced, the specifics of our traffic have been ignored along with the abolition of national rules. There are no traffic rules published in FAI documents governing the conduct of sailplane competitions. That is why when we meet together at competitions, we can adapt regulations, which aeroclubs have had for years, as good practice or aviation etiquette. As a general rule of thumb, let's assume that a sailplane that is flying behind another sailplane is responsible for separation and safety as a sailplane flying in front cannot see what is happening behind.Secondly, avoid sudden maneuvers in the immediate vicinity of the second sailplane. The closer we fly, the slower the approach speeds and the smoother the maneuvers should be. Flying head on deviate to the right.  And specifically for our  1a) Never fly over another sailplane in such a position and so close that you lose sight of it under the fuselage and when it is possible that a sailplane below may pull up and collide with those flying above. When the pilots cannot see each other, a collision is highly probable. This should be avoided in straight flight at high speed when pulling up may change altitude very fast, but also when circling in the thermal. Overtaking vertically on the final is especially dangerous. Fly at least a wingspan aside. 1b) - You must not overtake when flying under another sailplane in a position where a sailplane flying above could dive and collide with you.

2a) - Circling sailplanes have priority. They fly at a slower speed and have less maneuverability. The gliders in the thermal need to focus on observing each other. If you want to join a thermal you should also respect the job pilots already did to find a core.  2b - When joining the thermal, it should follow a tangent line to circling sailplanes and join in the same direction of circling. Adjust the speed as early as possible and be careful not to collide with the sailplane above when you pull up. Look around. In the vicinity of the thermal there may be gliders circling in a different orbit or gliders approaching the thermal from a different direction, which sets a particular risk of collision.2c) - When gliders enter the same thermal accidentally and start circling in opposite directions, the higher glider sets the direction of circling. If the vertical separation is over 300m, you can circle in opposite directions, but if gliders enter the thermal at altitudes in between, they should start circling in the same direction as the highest glider, so it is better to adjust the direction of circling in advance if you are the lower glider.2d) - When leaving the thermal, before you start to accelerate, make sure that there is no glider below. When you leave a crowded thermal, it is better to accelerate after you level off your wings. Especially Dangerous situations are when more than one glider leaves or enters the thermal at the same moment. In this case, you should check the position of each glider in the vicinity several times during the entry.
3- Flying by the mountain slope, give way to the glider with the slope on his right side. The usual rule of right-hand traffic does not allow him to deviate to the right to pass, and for this reason, the glider with a slope on the left has the option of flying wider into the valley and giving way. The exception is the left end of the slope (looking against the wind), where immediately after making the turn, gliders that were flying directly behind us and are still before the turn should be given way.