These recollections are from my childhood & "teenhood" in "Atlantic City, New Jersey, 1950s and mid 1960s} and from my observation of children in Pittsburgh, PA {from the late 1960s to date}:

My memories/observations of "It Tag" {the name that I recall from my childhood & the name that appears to be used most often among African American children in Pittsburgh} is confused with memories & observations of the game of "Hide & Go Seek".

You have to have a person who is "It" for both "It Tag" and "Hide & Go Seek".

Apart from self-selection, adult selection, or the "coronation" of a child with a strong personality as "It" by other children, children choose "It" by a process of elimination. Kids huddle in a bunch in front of the "reciter" {this is my term; I don't recall that any referent was used for this person}. Each of the kids either stuck their right foot out in front of the reciter OR each of the kids would stretch out their right arm so that their right fist would be within reach of the reciter. The kids are silent while the reciter chants most of the choosing "It" rhyme. The reciter touches the outstretched foot of each child {or their outstretched fist} while he or she recites a word or, in some cases, a syllable of the rhyme. One common rhyme {from my childhood and one that I've still heard nowadays} is:

My mother and your mother
were hanging out some clothes.
My mother punched your mother
right in the nose.
What color was the blood?
[At this point the person whose foot or fist was touched chooses a color. "Red" was the usual color that was chosen. The reciter then continues with the rhyme]
R-E-D spellls Red
And you are OUT

[The rhyme is then repeated again and again until there is only one person remaining. That person is "It". Of course, that rhyme can be manipulated to increase the chances that someone the reciter is friends with will be chosen as "It". One way of manipulating the rhyme was nstead of that last line given above to say:

"And you are not the one to be "It"

When "It" is selected [by the group, or self-selected, or selected by a teacher or summer camp group leader], he {or she} closes his eyes, puts his right hand over his eyes and then starts this counting while the rest of the group {including the reciter} scurries around looking for good hiding places.

"It" counts "1-2-3-4-5-6-7-8-9-10 [Usually this is chanted fast]. "It" will then say "Are you ready?" [Usually the first time "It" says this a couple of kids who haven't found good hiding places will respond "NO!". "It" will then repeat his count, and then say again "Are you ready?" Someone may still not have found just the right hiding place, and will therefore shout "NO!". "It" will count again to give that person more time. After the second or third time this happens, "It" will say "READY OR NOT, HERE I COME!" "It" will then start looking for people. When he {or she} finds a kid, that person tries to run to Home base before being tagged {touched} by "It" . If the person reaches "home base" he or she is "Home Free".

My memory of home base is like what Becca72 wrote in her 07 Aug 07 - 11:02 AM post.

Presumably, the last person who is tagged becomes the next "It" . Or maybe they become the reciter.