I don't think it's possible on here, not all BBcodes are supported on these forums.

To answer your question though it's
[post=insert post number]insert what you want to call it here[/post]

The date/time of the post above the poster's name is the unique URL and can be used to jump to the post.

As an example, I used Cocobell's post:
test

all you need to do is quote the post and see what's in the code.
it is {http://us.ohmydollz.com/board/viewtopic.php?pid=266456#p266456}
for specific post
or {url=http://us.ohmydollz.com/board/viewtopic.php?id=8742&p=3}
for specific page
or {url=http://us.ohmydollz.com/board/viewtopic.php?id=8742}
for the 1st page.

I think the easiest way to "jump" to a specific post is to click on the date/time of the post you want to jump to and copy the url address.

So step by step:
1. Look for the post you want to jump to. I choose Cocobelle's post from this thread.
2. Look at the date/time on the top left corner of the post. The one I've chosen shows "2014-02-02 10:51:15". Left-click on it.
3. The web address in the url bar will change. Mine shows "http://us.ohmydollz.com/board/viewtopic.php?pid=267530#p267530". Copy it.
4. Write your message by putting the copied web address inbetween [ur.l] and [/ur.l] (without the dots of course). Mine looks like this [ur.l]http://us.ohmydollz.com/board/viewtopic.php?pid=267530#p267530[/ur.l] and if done properly shows this http://us.ohmydollz.com/board/viewtopic … 30#p267530. If you click on it, it should lead you to the chosen post.

Instead of clicking you can also try the "Copy Web Address" (or something like that, depends on the web browser). You just have to right-click on the date/time of the post and choose the "Copy Web Address" from the list. Then you put the copied address inbetween the "urls" :)

Hope that helps!