depending on how aggressive your fish are, you can stick your fingers in the tank while holding a cube, and just roll it around and squeeze it. i generally only do this will juvi's and however.
the turkey baster idea works great. just make sure you buy a brand new one, dont use soap on it, and only use it for your tanks from now on
I thaw mine out first then drop the cube in the tank...This way it stays together and the fish pick at the cube...I don't like the food spread all over the tak b/c it's get in my filter.
the people at my lfs say to let defrost. i let bloodworms defrost in a small glass, then pour the water with the bloodworm scent in so all my fish are out and ready to eat rather than my tinfoil and redhook silverdollar eating it all
For large frozen food such as market shrimp, fish filets, chunks of beefheart, chichen liver etc. Thaw out completely, something like this could damage the fish if they were to try to eat it. One of my 25" silver aros actully swallowed a frozen shrimp that accidently got into the tank. She didn't seem to care though, but caused me a few weeks of worrying.
For smaller prepared food, bloodworms, brine shrimp, beef heart. etc. as long as the fish are not swallowing the cube whole it is fine to just drop it frozen into the tank. This also keeps the food floating for a while which can be an advantage. The food can be consumed by the fish before it makes it's way into the filters.
One disadvantage to throwing in a frozen cube is that the aggressive feeders will get more and some shy fish may get none. If this is the case then it would be better to thaw out so you can distribute through out the tank evenly.
If i bought it in the cubes things i just toss it in and let deforst and the rest of the stuff thats not cubes i use clean to fu container and put my aquarium water and let it deforst and put it in