Toothless initially shown shy to Cloudjumper, but when the dragon babies were bothering him and the fear became friends, even when she felt intimidated by Valka's Bewilderbeast, Toothless hid under his wing (this is the scene most remembered of both).
During the rest of the movies both have a friendship in which you see them, for example, sharing food and other things. It is a relationship of friendship.
Unlike Toothless, Cloudjmper is very serious, and usually grunts at the Night Fury. The two do become closer over time, and Cloudjumper became of a brother-like figure to the Night Fury. This can be seen from time to time like when Toothless tries to catch Cloudjumper's attention and as when Cloudjumper regurgitated some fish for him. Cloudjumper is also very noble and is a dragon of well‐balanced character as when Toothless becomes the new Alpha, the proud Stormcutter respectfully bows to him, a younger and newer dragon even though he has been serving in the Dragon Den.
As with Stormless, the Dragons they tend to humanize the stories to improve communication in the fanfic.
Note: Please only add examples that are part of the RotBTD fandom.