Shorten posts…

I want to use shortened versions of my blog posts that require a visitor to click a link to view the full post.

Im using a custom theme that I don’t want to change but can’t find a way of doing it. Is there a piece of codeI could edit to allow this?

my website is ww.club1985.com and any help would be greatly appreciated.

The site is not safe for work however.

Thanks