I recently used some perforated bricks (ten holes) and found them really awkward to lay. Even with quite a stiff mix, lots of mortar fell down the holes and the slight movement due to laying a second brick would cause the first brick to sink down as mortar was displaced upwards into the holes.
A quick web search revealed no advice specific to perforated bricks, so I just carried on as best I could, making the mortar stiffer and stiffer, as I needed to get finished and this was non-critical work - just two courses of Class B engineering bricks to go under a timber shed.
Obviously my technique was at fault, please Woody can you suggest what I was doing wrong? In the past I have used Flettons and solid concrete blocks without difficulty (amateur jobs such as garden walls), but these perforated bricks seemed like the invention of the devil, and I kept wishing I had paid the extra and bought solids.
Without seeing how you were laying the bed and then forming the trough, its hard to say.
But generally you should lay the bed, then angle the sides (45-60° or so), and that gives a solid mass. Then when you form the trough this compacts the mortar, partly fills perforations, and spreads it evenly ready to place the brick on it. Then you cut the excess off.
Done right, this will be enough mortar to allow you to press the brick down without tapping, the perforations fill up, and the bed is solid, and just enough mortar squeezes out which you cut off and use for vertical joint of the next brick.
Done wrong, the bricks sink or may be uneven, you may need to add mortar to the bed, or its too much and it all flops out and you are banging the bricks down.
It does take practice and with experience you get the right amount. The idea is is that you do all this with the least amount of motion and number of moves - no repetitive bending and picking up mortar or returning excess to the spot board.
This is why the perforations help as they fill when you press the brick down. With solid beds, you need to be even more careful as the mortar will have to come out of the sides instead, and it its too much its hard to get the brick own or worse the excess slides down the face of the wall or in the cavity.
and even then sometimes the bricks dont go down properly so you lift them up and add a bit more mortar. Also you can't slide the brick and so need to tap it down.
