jiraiya does tell naruto not to become too hot headed and to get a grip on himself before he loses control right before he says to not use that jutsu, so i don't think the 4th tail being "that jutsu" should be ruled out
jiraiya does tell naruto not to become too hot headed and to get a grip on himself before he loses control right before he says to not use that jutsu, so i don't think the 4th tail being "that jutsu" should be ruled out