Personally I'd advise against just lobbing in a frozen block to your fish. Generally speaking there is a lot of crap that's held with frozen bloodworm, and you'd be chucking all of this into your tank.
Get some tank water in a cup/tub/glass, stick the frozen bloodworm into this for a few minutes. The iceblock will melt leaving the bloodworm 'free' with a few good stirs. I tend to tip most of the blood water away, refill the glass with fresh tank water and then put it back into the tank.
Usually i use some sort of pipette to suck up the bloodworm/water and disperse it around the tank evenly. That's not really necessary though, i just like to make sure everyone gets a share and very little hits the substrate.