Wibbly wobbly, timey wimey

"A big ball of wibbly wobbly, timey wimey stuff" was how the Tenth Doctor described time to Sally Sparrow through a DVD Easter Egg. Though he quickly admitted that the sentence had "got[ten] away from [him]", the term was soon thereafter applied to an invention of his, the timey-wimey detector. (TV: Blink) He used it at least once afterwards when trying to think. (PROSE: Prisoner of the Daleks) Though it was seemingly his tenth incarnation who coined it, the Fifth Doctor was familiar enough with the expression to complete the phrase when the Tenth Doctor started it. (TV: Time Crash)

The Doctor began using "wibbly wobbly, timey wimey" and variations with greater frequency following his regeneration into the Eleventh Doctor. (TV: The Eleventh Hour, The Doctor, the Widow and the Wardrobe, The Angels Take Manhattan, The Day of the Doctor) The term lent itself to two other devices during this incarnation: the wibbly lever and the timey-wimey distress beacon. (TV: The Wedding of River Song, Time)

When the Eleventh Doctor used it in front of the War Doctor, the Tenth Doctor, embarrassed, claimed he "[had] no idea where he gets that from". The War Doctor ridiculed his successors, asking the two why they insisted on talking like children. (TV: The Day of the Doctor)

During the overnight invasion of trees, the Year 8 Gifted and Talented Group of Coal Hill School drafted a speech to tell the people of the Earth to leave the trees alone. Amongst the chatter of the children, one of them said "timey wimey". (TV: In the Forest of the Night)