If you see a comma after a conjunction, it is pretty close to always wrong. There is a normal use, but not usually.
"and" can be used as a coordinating conjunction or as a list or to join two nouns. (This applies to all conjunctions, not just and.)
Coordinating Conjunction:
- He went to the store and bought milk. (Without the pronoun a second time)
- He went to the store, and he bought milk. (With the pronoun a second time)
List:
- He has a pencil, a notebook, and a math book. (Chicago style)
- He has a pencil, a notebook and a math book. (AP Style)
Join two nouns:
- Jack and Jill stopped by.
- The sides were peas and brussel sprouts.
Ok, now in none of these sentences is there a comma after the word "and".
Now, what if you add an interrupter or parenthetical element immediately after the word "and"?
Unfortunately, andyvn22 led you astray ever so slightly by saying the comma is allowed to offset the interrupter or parenthetical element. He forgot the rule that the interrupter or parenthetical element doesn't need a comma at the start if it begins a sentences or follows a conjunction.
Coordinating Conjunction:
- He went to the store, and with little thought, bought milk. (Without the pronoun)
- He went to the store, and with little thought, he bought milk. (With the pronoun)
Because these are coordinating conjunctions, the and is already a separator and no additional separator, such as a comma, is needed for the parenthetical element.
In the first sentence, even though a comma is not required because the second sentence cannot stand on its own, the comma is used before the coordinating conjunction because a parenthetical element follows it and strengthens the need for the comma.
List:
- He has a pencil, a notebook, and just sticking out of his backpack, a math book. (Chicago style)
- He has a pencil, a notebook, and just sticking out of his backpack, a math book. (AP Style)
Now, AP style will have the comma in this situation, and so both AP and Chicago are the same.
As you see, because "and" is already a separator, you don't need a comma for an interrupter or parenthetical element. However, an interrupter or parenthetical element strengthens the need for a comma before the conjunction. I know this contradicts what andyvn22 says. So a comma is allowed, but it is allowed before the conjunction, not after.
What about this: "A sentence must still be grammatically correct when removing the interrupter or parenthetical element?"
While that statement is correct, that doesn't mean the comma should be after the conjunction. The logical flaw that might lead one to believe this is assuming that when removing the interrupter or parenthetical element that you also remove the conjunction. You don't. The conjunction is not removed with the interrupter or parenthetical element just because a comma precedes the conjunction. Now, removing the interrupter or parenthetical element may weaken the need for a comma and you may end up removing the comma, too, but that doesn't mean the comma or the conjunction were part of the interrupter or parenthetical element.
Join two nouns:
- Jack and, to my joy, Jill stopped by.
- The sides were peas and, to my distaste, brussel sprouts.
Here the conjunction is not coordinating, and not already separated by a serial comma.
So, when should and be followed by a comma?
Answer:
- When the
and is not a coordinating conjunction or not in a serial making the serial comma available.
- When you are talking about the words themselves and not using the word. For example, if you want to list all the conjuctions:
and, but, or, yet, for, nor, so. That is the only time a comma should follow a conjunction.
Don't think that just because you see a comma after a conjunction in your favorite author's novel that it is correct. This is a very obscure rule and many, many writers get it wrong.
