$$B :w2: tenuki
$$ . . . . . . . . . . . |
$$ . , . . . . . , . . . |
$$ . . . . . . . . X . . |
$$ . . . . . . . . . . . |
$$ . . . . . . O b O . . |
$$ . . . . . X 1 3 a . . |
$$ . . . . . . . O . . . |
$$ . X . . . X . , O . . |
$$ . . . . . . . X O . . |
$$ . . . . . . . . X X . |
$$ . . . . . . . . . . . |
$$ ----------------------
- Click Here To Show Diagram Code
[go]$$B :w2: tenuki
$$ . . . . . . . . . . . |
$$ . , . . . . . , . . . |
$$ . . . . . . . . X . . |
$$ . . . . . . . . . . . |
$$ . . . . . . O b O . . |
$$ . . . . . X 1 3 a . . |
$$ . . . . . . . O . . . |
$$ . X . . . X . , O . . |
$$ . . . . . . . X O . . |
$$ . . . . . . . . X X . |
$$ . . . . . . . . . . . |
$$ ----------------------[/go]
If White tenukies, Black should simply push making miai of 'a' and 'b'.
$$B :w2: tenuki
$$ . . . . . . . . 8 . . |
$$ . , . . . . . , . . . |
$$ . . . . . . . . Y . . |
$$ . . . . . . . 4 6 . . |
$$ . . . . . . O 3 O . . |
$$ . . . . . X 1 5 7 . . |
$$ . . . . . . . O . . . |
$$ . X . . . X . , O . . |
$$ . . . . . . . X O . . |
$$ . . . . . . . . X X . |
$$ . . . . . . . . . . . |
$$ ----------------------
- Click Here To Show Diagram Code
[go]$$B :w2: tenuki
$$ . . . . . . . . 8 . . |
$$ . , . . . . . , . . . |
$$ . . . . . . . . Y . . |
$$ . . . . . . . 4 6 . . |
$$ . . . . . . O 3 O . . |
$$ . . . . . X 1 5 7 . . |
$$ . . . . . . . O . . . |
$$ . X . . . X . , O . . |
$$ . . . . . . . X O . . |
$$ . . . . . . . . X X . |
$$ . . . . . . . . . . . |
$$ ----------------------[/go]
It's bad to wedge as Black's stone can become damaged and White gain's more options to settle.
$$B
$$ . . . . . . . . . . . |
$$ . , . . . . . . . . . |
$$ . . . . . . . b X a . |
$$ . . . . . . . . . . . |
$$ . . . . . . O . O . . |
$$ . . . . . X X O . . . |
$$ . . . . . . . O . . . |
$$ . X . . . X . , O . . |
$$ . . . . . . . X O . . |
$$ . . . . . . . . X X . |
$$ . . . . . . . . . . . |
$$ ----------------------
- Click Here To Show Diagram Code
[go]$$B
$$ . . . . . . . . . . . |
$$ . , . . . . . . . . . |
$$ . . . . . . . b X a . |
$$ . . . . . . . . . . . |
$$ . . . . . . O . O . . |
$$ . . . . . X X O . . . |
$$ . . . . . . . O . . . |
$$ . X . . . X . , O . . |
$$ . . . . . . . X O . . |
$$ . . . . . . . . X X . |
$$ . . . . . . . . . . . |
$$ ----------------------[/go]
White 'a' and 'b' are miai. But Black prefers White 'a' over 'b' for the Low-Chinese opening.
$$B
$$ . . . . . . . . . . . |
$$ . , . . . . . 3 a . . |
$$ . . . . . . 4 2 X d . |
$$ . . . . b . . c . 1 . |
$$ . . . . . . O . O . . |
$$ . . . . . X X O . . . |
$$ . . . . . . . O . g . |
$$ . X . . . X . f O . . |
$$ . . . e . . . X O . . |
$$ . . . . . . . . X X . |
$$ . . . . . . . . . . . |
$$ ----------------------
- Click Here To Show Diagram Code
[go]$$B
$$ . . . . . . . . . . . |
$$ . , . . . . . 3 a . . |
$$ . . . . . . 4 2 X d . |
$$ . . . . b . . c . 1 . |
$$ . . . . . . O . O . . |
$$ . . . . . X X O . . . |
$$ . . . . . . . O . g . |
$$ . X . . . X . f O . . |
$$ . . . e . . . X O . . |
$$ . . . . . . . . X X . |
$$ . . . . . . . . . . . |
$$ ----------------------[/go]
If

, then between 'a' and 'b' White either settles -- better than if Black had played 'c' and allowed White 'd' -- or moves out into the center taking Black's key expanding point for his bottom moyo around 'b' and exacerbating White's invasion at 'e'. Black 'f' for 'g' may no longer be sente when the time comes. Black's choice of which direction to attack White becomes worse.
$$B
$$ . . . . . . . . . . . |
$$ . , . . . . . . 5 3 . |
$$ . . . . . . . . X 2 . |
$$ . . . . . . . . . 4 . |
$$ . . . . . . O 6 O . . |
$$ . . . . . X 1 a . b . |
$$ . . . . . . . O . c . |
$$ . X . . . X . , O . . |
$$ . . . d . . . X O . . |
$$ . . . . . . . . X X . |
$$ . . . . . . . . . . . |
$$ ----------------------
- Click Here To Show Diagram Code
[go]$$B
$$ . . . . . . . . . . . |
$$ . , . . . . . . 5 3 . |
$$ . . . . . . . . X 2 . |
$$ . . . . . . . . . 4 . |
$$ . . . . . . O 6 O . . |
$$ . . . . . X 1 a . b . |
$$ . . . . . . . O . c . |
$$ . X . . . X . , O . . |
$$ . . . d . . . X O . . |
$$ . . . . . . . . X X . |
$$ . . . . . . . . . . . |
$$ ----------------------[/go]
If

rather than 'a', then White 'b' or 'c' later makes worse eye potential, leaves more bad aji, and gives Black's stones an extra liberty. The liberty could become crucial in the variations following White's invasion at 'd'.
I hope this answers your questions.