Tailed Beast Control

Throughout the series, several shinobi, jinchūriki or not, have demonstrated the ability to gain control of one or more of the nine tailed beasts. The cause and effect of this control varies between those capable of doing it. However, only five people are known to have full control of the tailed beasts' power: Madara Uchiha, Hashirama Senju, Yagura, Killer Bee, and Naruto Uzumaki.

Jinchūriki
The jinchūriki have the potential to control their tailed beasts through willpower and concentration, but requires a lot of training in order to retain it. If an inexperienced jinchūriki transforms deeper into his or her tailed beast's forms, his or her personality tends to corrode into animal instincts, becoming more ferocious in battle, but increasingly dangerous to his or her friends and allies. The best possible training spot for the jinchūriki to control their tailed beasts is at the Falls of Truth.

Gaara, even before he started to take the One-Tailed Shukaku's form, was constantly plagued by it; whenever Gaara slept, Shukaku would eat his personality and influence him with its bloodlust behavior, causing insomnia, a trait that all of Shukaku's jinchūriki share. By the time Part II began, Gaara gained better control over Shukaku, and was even capable of using Shukaku's arms to attack numerous times, without losing control of himself. After Shukaku was extracted from Gaara by Akatsuki, and he was revived by Chiyo, Gaara is no longer in any danger of losing control.

Experienced jinchūriki, like Yugito Nii and Rōshi, were able to control the abilities given by their tailed beasts at will, but they were not able to completely control the beast themselves. However, in the anime, Utakata seemed to have a better relationship with his tailed beast than most, as he could ask it to fully release its power without it forcefully overtaking Utakata's consciousness. His beast, the Six-Tailed Slug, accomplished only the task wished by Utakata and retreated back into him without any resistance.

Yagura and Killer Bee were the two jinchūriki to retain full control and complete consciousness of their tailed beasts and their forms. But this type of control, at least seen with Killer Bee, involves the beast's own cooperation, instead of forced obedience. Because of his relationship with the Eight-Tailed Giant Ox, Killer Bee is in no danger in its presence, even sitting on top of its muzzle from time to time.

In the beginning, Naruto Uzumaki couldn't control Nine-Tailed Demon Fox's power. Although a number of methods had been devised to break the Nine-Tails' influence over Naruto (Jiraiya's seal tag, and Yamato's Hokage-Style Sixty-Year-Old Technique - Kakuan Entering Society with Bliss-Bringing Hands, which was facilitated by Hashirama Senju's necklace Naruto wore before its destruction), Naruto simply limited his use of the Nine-Tails' chakra and tried not to allow his anger get the best of him. According to Gerotora, whenever Naruto drew out the Nine-Tails' chakra, its will containing its massive amount of hatred would fuse along with it, relentlessly trying to control Naruto whenever given the chance. To control its power, Naruto must have his own will and heart both very strong and free of hatred, in order to separate the Nine-Tails' will from its chakra completely. After receiving help from his mother, Kushina Uzumaki, through her words of encouragement and restricting the Nine-Tails' movement with her chakra chains, Naruto finally managed to have full control of the Nine-Tails' Yang chakra, gained a new form, and imprisoned the Nine-Tails itself with a new seal.

Non-Jinchūriki
Hashirama Senju, the First Hokage, could control the tailed beasts using his Hokage-Style Sixty-Year-Old Technique - Kakuan Entering Society with Bliss-Bringing Hands, which utilizes the power of his Wood Release kekkei genkai to forcibly suppress the tailed beasts' chakra.

Madara Uchiha could subdue the Nine-Tails using his Eternal Mangekyō Sharingan, and had done it at least twice. When Madara has to control the Nine-Tails, he focuses on the beast's eyes, and the Sharingan will appear over them, and then the Sharingan's tomoe disappears as the pupil enlarges. When Madara had full control, he could then use the Summoning Technique to transport the Nine-Tails to where he wanted it. He has used it once to transport the Nine-Tails right into Konoha itself. Sasuke Uchiha had also used the Sharingan against the Nine-Tails within Naruto's subconscious, but only to suppress its chakra.

In the anime, a filler character, Yūkimaru, was able to partially control the Three-Tailed Giant Turtle, the former beast of Yagura.