The only way I can do it, is not actually sink them, but with a pair of tongs, hold the block at the bottom of the tank, and let them defrost once in the tank..
If you hold the cube (or part of one) under the surface for a few moment and shake it while rubbing your fingers together they will become saturated quickly and separate from each other. Once they are wet they will drift down to the bottom.
Freeze dried bloodworms provide good nutrition for fish when live or frozen are not available, but it's best if they are reconstituted rather than dry when the fish eat them.
For those type, simply put the amount you want to feed into a shallow cup or small bowl and add water. Then you take a spoon or your fingers and squeeze the air out of them. When they are saturated enough they will sink slowly.
I have the same kind you have what I do is throw a pinch right in front of the filter. The filter will carry it around and eventually it will hit the ground. What fish are you trying to feed these two. The two bottom feeders I have are clown loaches and Columbian sharks and when I feed them those its gets to them just fine.