write code for a Shopify Site to include a read more link in collections

We would like to add a "read more" link on the collections page of our shopify collections (we have approximately 7 of these collections). We don't want all of the SEO keyword description to show on the website, esp the mobile site, but we still want that keyword rich material in the description. But if it is part of a "read more" link then it can sit there, but not necessarily have to be seen on the site, unless someone clicks on it. Basically we are trying to truncate the collection description.