When you first encounter Ustengrav as part of retrieving the Horn you will find a note in its place. Besides the note, the altar is otherwise useless. Follow the note, obtain the horn, and return in to the Greybeards.. But your journey in Ustengrav is not over.

If you return to Ustengrav and make your way back to the altar, you'll notice that the horn has found its way back. Not only that, but you can activate the altar and receive a free Dragon soul.

If you press the Activate button rapidly, you will be granted 2 Dragon souls instead of one. This information is not in the wiki, so if someone would care to add it, I would be greatly appreciative.

Happy Hunting!

EDIT: I added the information to the wiki.

Good information. Thank you.

You're welcome. Not sure how many people knew about this so I wanted to share it.

I heading back there tonight to check this out. It was a cool dungeon. Was there anything to slow you down when you went back?

I read some info on uesp.net (not sure it was your post) and when the time came to do the quest, verified the "free dragon soul" part. And with a quick tapping of the E key, I managed to get as most as 6 souls from it.
Did 10 tries eventually:

3 times i got: 1 soul
4 times i got: 4 souls
2 times i got: 5 souls
1 time i got: 6 souls

And that's where I continued my game from, but I think it's possible to get more out of it, maybe with further testing this will be proven.

I also posted this on the uesp.net skyrim talk section about the quest, on pc

I'm guessing this is a glitch? Or an exploit...

Not sure if it's worth the hasle myself, apart from being interesting. Not like dragons are hard to find (or kill).

That's a nice info you got there! Thanks!

I don't know, but they're as rare as hens teeth in my Skyrim. I've seen the big one twice near Riften, and once around Riverwood, but he always flew off, no others seen in days.

Ooh, nice. This is an exploit that I might actually use, as well, seeing as dragons irritate me and it's not exactly difficult to get souls as it is. And I only use a select few shouts of the 20-25 odd we get given.

Yeah, I'm finding that dragons are not so common in my skyrim games either and I've played 444 hrs. They do seem to congregate around Riverwood when I'm trying to buy smithing stuff though, lol.

I was only able to squeeze out just one dragon soul when I returned.

make a save right before the altar and just keep trying it. stand in different places. the first couple of times, note the timing of when you activate and when the soul animation starts and mess around with when you start hitting activate and how fast. eventually you'll get more than 1.

Just how did you got 6?? I can't even get it up to 3 souls, just how fast did you spam activate it??

Thanks for the info OP, I'm going to head back there tomorrow to stock up on dragon souls.

How did you get through the gates, when I shout I only get the first gate

Run over the three pressure plates normally, then use the Whirlwind Sprint immediately after hitting the third plate.

Tapped really fast E on my keyboard and at the end went from 10 to 16 souls, that was the most...

Nice, thank you.

I'm not having any problem finding dragons. I'd like to re-name Molag Baals mace 'the fly swatter'. Dragons appear everytime I clear a dungeon. They appear every time I excit a city after completing a quest. They appear just for funsies when I'm out exploring steep mountains.
When I go out specifically to kill a dragon, ie a 'kill the dragon at wherever' two or three will show up.

I'm not complaining, it's truly awesome to see two or three of these gigantic creatures cutting through the sky screaming rage and flames and ice and blood in my general direction. They're a truly terrifying aspect of Skyrim that I love the most.


But I gotta wonder... why me?

Considered changing your aftershave perhaps?