He's not usually like this.
5 seconds sound clip from the How to Train Your Dragon movie soundboard.
You can hear this line at 00:53:40 in the Blu-ray version of the movie.
Quote context
[...]
- See? Nothing to be afraid of. Whaaah!
- Toothless! What is wrong with you? Bad dragon!
- Oh, no.
- Toothless, what are you doing? We need her to like us!
- Thank you for nothing, you useless reptile.
- OK, I am sorry! I'm sorry. Just get me off this thing.
[...]