Ticks carry Lyme and other diseases, with the viruses breeding mostly in the digestive system. If, in trying to remove the tick, you squeeze it's body, you cause the tick to regurgitate the contents of it's "stomach" back into your body with a concentrated load of virus.
I've tried the "heat " method of removing ticks; he didn't back out but I did kill him with the heat. I don't think that works well.
I've tried alchohol too, but with no better results. Who knows, a drunk tick might vomit right into your bloodstream.
Since ticks don't have a corkscrew shaped head, I don't know where the "twist him out" myth came from. There's too much a chance of twisting his little head off, violating the First Rule.
You need a tick-tool that can get between your skin and his body and lift. Very small pointed tweezers or a special spoon with a narrow claw-hammer-like slot would be best. Slip the tool under his body and gently lift until your skin puckers outward, then pause. The tick will have a hard time holding his grip and will let go by himself taking all of his body parts with him. Pulling too hard may violate the First Rule.
Here is a more "official" site on tick removal with much more information. [an error occurred while processing this directive]