I recently took a class on mold building and was taught a different method for plaster preparation and filling molds.
When the water is filled in the bucket you add plaster until a small heap of plaster is emerging in the middle. If this heap remains for some seconds, there is a sufficient amount of plaster. After that you wait some minutes so that the plaster can absorb the water. After that you put your hand into the bucket to the very bottom and leave it there. And then you carefully circle your hand but only on the bottom without moving your arm up and down. You stir as long as you feel that there are no more lumps and the plaster getting slightly thicker. This way you incorporate as little bubbles as possible.
When ready you start pouring. First, you take only a little plaster just to cover the object for the mold and the bottom. This way, the object is secured to the bottom and the plaster can stiffen and will not leak through to the outside. You wait until the plaster hardens a little. With a cup you add then the remaining plaster until the object is covered about an inch above the highest point of the object. Recommendation was not to pour the plaster directly from the bucket into the prepared mold as it is better to add the plaster in small amounts.
Once all the required plaster is in the prepared mold you do not burp the mold but you constantly tap with the back of your hand/fingers on the surface of the plaster. This will activate the bubbles to come to the surface. And you do this until the plaster hardens. Advantage with this method is that the mold is moved as little as possible.
I have used this method since taking the class several times and am surprised at the much better quality of my molds compared to my previous ones where I poured all the plaster in at once and used burping. What I have to work on though is on better eyeballing the amount of plaster/heap to be used. In the past I have used the ratio as shared here in the table but weighing and measuring plaster and water is not my favorite task.