[SOLVED] User-friendly way to indent some paragraphs manually?

The Atahualpa default is to have posts in block paragraphs (not indented). I know how to use CSS to change the default so that all paragraphs are indented.

The problem is, when my students are writing practice essays I want most of their paragraphs to be indented, but not all of them. A block quotation, for example, should not be indented, nor should (usually) the first line following a block quotation, which is almost always a continuation of the same paragraph.

So: is there a user-friendly way for my students to indent their paragraphs manually? If they put spaces at the beginning of the first line of the paragraph, the spaces just disappear when the default is set to block paragraphs. Or, is there a user-friendly way for them to "un-indent" a paragraph when the default is set to indented paragraphs?

I am using 3.6.7.

Many thanks!

Eric