BuddyPress.org

Hi,
The description of my groups are too long, so I need show it into a toggle without to use a plugin.
At the moment I only have this, but I need expand and collapse the description:

function bp_excerpt_group_description( $description ) {
// your exceprt code
$length = 170;
$description = substr($description,0,$length);
return $description;
}
add_filter( ‘bp_get_group_description’, ‘bp_excerpt_group_description’);

Somebody can help me, please?
Thanks,