In Drupal, you can cause the teaser to end at the point of your choosing by either clicking in this button in TinyMCE or by adding the following to your content body: <!--break-->

Everything above this tag will appear in the teaser (unless you place it beyond the point at which Drupal automatically breaks the content).

Notes

• Make sure there are no spaces in the tag or it will be ignored.
• You can place the tag in the middle of a paragraph. The full text will not notice the tag so the paragraph will look normal, but the paragraph will be cut short in the teaser